diff --git a/.github/workflows/make.yml b/.github/workflows/make.yml
index b61291a4ae7..f399ae28829 100644
--- a/.github/workflows/make.yml
+++ b/.github/workflows/make.yml
@@ -342,3 +342,44 @@ jobs:
         artifactErrorsFailBuild: true
         prerelease: true
         replacesArtifacts: true
+  make-emscripten:
+    name: Make (Emscripten)
+    runs-on: ubuntu-latest
+    container: emscripten/emsdk:3.1.74
+    timeout-minutes: 30
+    defaults:
+      run:
+        shell: bash
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install dependencies
+      run: |
+        sudo apt-get -y update
+        sudo apt-get -y install gettext p7zip-full
+    - name: Build
+      run: |
+        emmake make -f Makefile.emscripten -j "$(nproc)"
+      env:
+        FHEROES2_STRICT_COMPILATION: ON
+    - name: Create package
+      run: |
+        # Translations and H2D files are already included in fheroes2.data
+        7z a -bb1 -tzip -- fheroes2_emscripten.zip LICENSE changelog.txt fheroes2.data fheroes2.js fheroes2.wasm ./docs/README.txt ./files/emscripten/*
+    - uses: actions/upload-artifact@v4
+      if: ${{ github.event_name == 'pull_request' }}
+      with:
+        name: fheroes2_emscripten.zip
+        path: fheroes2_emscripten.zip
+        if-no-files-found: error
+    - uses: ncipollo/release-action@v1
+      if: ${{ github.event_name == 'push' }}
+      with:
+        artifacts: fheroes2_emscripten.zip
+        body: ${{ github.event.head_commit.message }}
+        token: ${{ secrets.GITHUB_TOKEN }}
+        name: Emscripten build (latest commit)
+        tag: fheroes2-emscripten-sdl2_dev
+        allowUpdates: true
+        artifactErrorsFailBuild: true
+        prerelease: true
+        replacesArtifacts: true
diff --git a/.gitignore b/.gitignore
index af8057fc82b..3793277c993 100644
--- a/.gitignore
+++ b/.gitignore
@@ -92,7 +92,14 @@ android/.idea
 android/.gradle
 
 # Automatically created Android assets
-android/app/src/main/assets/files/
+android/app/src/main/assets/
 
 # Mac magic folders
 .DS_Store
+
+# Web build artifacts
+*.wasm
+*.wasm.map
+fheroes2.js
+fheroes2.data
+src/dist/web/dist/*
diff --git a/Makefile.emscripten b/Makefile.emscripten
new file mode 100644
index 00000000000..07feece5450
--- /dev/null
+++ b/Makefile.emscripten
@@ -0,0 +1,43 @@
+###########################################################################
+#   fheroes2: https://github.com/ihhub/fheroes2                           #
+#   Copyright (C) 2025                                                    #
+#                                                                         #
+#   This program is free software; you can redistribute it and/or modify  #
+#   it under the terms of the GNU General Public License as published by  #
+#   the Free Software Foundation; either version 2 of the License, or     #
+#   (at your option) any later version.                                   #
+#                                                                         #
+#   This program is distributed in the hope that it will be useful,       #
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of        #
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         #
+#   GNU General Public License for more details.                          #
+#                                                                         #
+#   You should have received a copy of the GNU General Public License     #
+#   along with this program; if not, write to the                         #
+#   Free Software Foundation, Inc.,                                       #
+#   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             #
+###########################################################################
+
+# Options:
+#
+# FHEROES2_STRICT_COMPILATION: build in strict compilation mode (turns warnings into errors)
+# FHEROES2_WITH_DEBUG: build in debug mode
+# FHEROES2_DATA: set the built-in path to the fheroes2 data directory (e.g. /usr/share/fheroes2)
+
+.PHONY: all clean translations
+
+all: fheroes2.js
+
+fheroes2.js: translations
+	$(MAKE) -C src/dist PLATFORM=emscripten
+	cp src/dist/fheroes2-ems/fheroes2.data .
+	cp src/dist/fheroes2-ems/fheroes2.js .
+	cp src/dist/fheroes2-ems/fheroes2.wasm .
+
+translations:
+	$(MAKE) -C files/lang
+
+clean:
+	$(MAKE) -C src/dist clean
+	$(MAKE) -C files/lang clean
+	rm -f fheroes2.data fheroes2.js fheroes2.wasm
diff --git a/Makefile.vita b/Makefile.vita
index 18a547c6b23..956ec8d6694 100644
--- a/Makefile.vita
+++ b/Makefile.vita
@@ -1,6 +1,6 @@
 ###########################################################################
 #   fheroes2: https://github.com/ihhub/fheroes2                           #
-#   Copyright (C) 2021 - 2024                                             #
+#   Copyright (C) 2021 - 2025                                             #
 #                                                                         #
 #   This program is free software; you can redistribute it and/or modify  #
 #   it under the terms of the GNU General Public License as published by  #
@@ -40,7 +40,7 @@ fheroes2.vpk: eboot.bin param.sfo translations
 		--add files/images/platform/psv/sce_sys/livearea/contents/template.xml=sce_sys/livearea/contents/template.xml \
 		--add files/data=files/data \
 		--add files/lang/vita_temp=files/lang \
-	fheroes2.vpk
+		fheroes2.vpk
 	rm -r files/lang/vita_temp
 
 translations: fheroes2.elf
diff --git a/android/app/build.gradle b/android/app/build.gradle
index 54991ba2fac..8167f0b5abc 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -99,6 +99,14 @@ tasks.register('copyH2D', Copy) {
     into 'src/main/assets/files/data'
 }
 
+tasks.register('copyTimidity', Copy) {
+    from('../../files/timidity') {
+        include 'instruments/*.pat'
+        include 'timidity.cfg'
+    }
+    into 'src/main/assets'
+}
+
 tasks.register('copyTranslations', Copy) {
     from('../../files/lang') {
         include '*.mo'
@@ -107,5 +115,5 @@ tasks.register('copyTranslations', Copy) {
 }
 
 preBuild {
-    dependsOn copyH2D, copyTranslations
+    dependsOn copyH2D, copyTimidity, copyTranslations
 }
diff --git a/files/emscripten/fheroes2.jpeg b/files/emscripten/fheroes2.jpeg
new file mode 100644
index 00000000000..d0d3f9f04e4
Binary files /dev/null and b/files/emscripten/fheroes2.jpeg differ
diff --git a/files/emscripten/index.html b/files/emscripten/index.html
new file mode 100644
index 00000000000..99352febb69
--- /dev/null
+++ b/files/emscripten/index.html
@@ -0,0 +1,210 @@
+<html lang="en">
+<head>
+  <title>fheroes2</title>
+  <link rel="preconnect" href="https://fonts.googleapis.com">
+  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+  <link href="https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap" rel="stylesheet">
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/progress.js/0.1.0/progress.min.js" integrity="sha512-CklrzCqwODBOEJHJq73SZrgWC7xcxssgg5M1xokosfDDz2/nLTCuMDyc51gbJtb8DriV4EYjJSlklPH5Ejn9XA==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
+  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/progress.js/0.1.0/progressjs.min.css" integrity="sha512-ovRFHsWpnYUBNZd/8CmbaWAKBDO8xb0l5Y8PdIae1O5RXO2QyU3CZGNzuYuE0CQHKazIzWMQpnTn26WpPjexfw==" crossorigin="anonymous" referrerpolicy="no-referrer" />
+  <style>
+      body { margin: 0; height: 0; font-family: "Roboto", serif;}
+      #canvas {
+          height: 100vh;
+          width: 100vw;
+          display: block;
+          margin: 0 auto;
+          background: url(./fheroes2.jpeg) center center;
+          background-size: cover;
+          position: absolute;
+          z-index: 10;
+      }
+      #uploader, #launcher {
+          z-index: 100;
+          position: absolute;
+          color: #fff;
+          font-size: 30px;
+          text-stroke: 1px #000;
+          -webkit-text-stroke: 1px #000;
+          height: 100vh;
+          width: 100vw;
+      }
+      #launcher {
+          display: none;
+          text-stroke: 1px #fff;
+          -webkit-text-stroke: 1px #fff;
+      }
+      #uploader input[type=file] {
+          display: none
+      }
+      #uploader label {
+          text-align: center;
+          display: block;
+          cursor: pointer;
+          height: 100vh;
+          width: 100vw;
+          position: absolute;
+      }
+      #uploader label span {
+          padding: 10vh 0 0 0;
+          display: block;
+      }
+      #launcher button {
+          font-size: 30px;
+      }
+      #launcher .buttons {
+          text-align: center;
+          padding: 10vh 0 0 0;
+      }
+  </style>
+</head>
+<body>
+<canvas id="canvas" width="640" height="400"></canvas>
+<div id="uploader">
+  <label>
+    <span>Click to select your Heroes 2 folder</span>
+    <input
+        type="file"
+        directory="directory"
+        multiple
+        webkitdirectory="webkitdirectory"
+        id="files"
+    />
+  </label>
+</div>
+<div id="launcher">
+  <div class="buttons">
+    <button onclick="Module.startGame()">Start game</button>
+    <button onclick="Module.deleteFiles()">Delete files</button>
+  </div>
+</div>
+<script>
+    const S_IFMT = 61440; /* 0x0170000 type of file */
+    const S_IFDIR = 16384;  /* 0x0040000 directory */
+    const progressBar = progressJs("#canvas").setOptions({
+        theme: 'blueOverlayRadiusWithPercentBar',
+        overlayMode: true,
+        considerTransition: true
+    });
+    const canvas = document.querySelector('canvas');
+    canvas.oncontextmenu = event => event.preventDefault();
+    Object.assign(window, { Module: {
+            preRun: [
+                () => Object.assign(window.ENV, {
+                    FHEROES2_DATA: `/fheroes2/data`,
+                    HOME: '/fheroes2'
+                }),
+                () => {
+                    addRunDependency('syncfs');
+                    FS.mkdir('/fheroes2');
+                    FS.mount(IDBFS, { root: '/' }, '/fheroes2');
+                    FS.syncfs(true, (err) => {
+                        if (err) throw err;
+                        try {
+                            if (Object.keys(FS.lookupPath(`${ENV.FHEROES2_DATA}`)).length === 0) return;
+                            document.querySelector('#uploader').style.display = 'none';
+                            document.querySelector('#launcher').style.display = 'block';
+                        }
+                        catch (ignore) {
+                            FS.mkdir(`${ENV.FHEROES2_DATA}`);
+                        }
+                    });
+                },
+                () => {
+                    document.querySelector('input[type=file]').addEventListener('input', e => {
+                        const files = [...e.target.files];
+                        const requiredFiles = ['data/HEROES2.AGG', 'data/HEROES2X.AGG']
+                        if (files.length === 1) return Module.clearInput('zip archives are not supported yet, sorry');
+                        if (files.length > 3000) return Module.clearInput('wrong directory, or your maps collection is really awesome.');
+                        const requiredResolved = files.filter(({ webkitRelativePath: path }) =>
+                            requiredFiles.some(rq => path.toLocaleLowerCase().endsWith(rq.toLocaleLowerCase()))).length === 2;
+                        if (!requiredResolved) return Module.clearInput('wrong directory');
+                        const whitListed = ['data', 'heroes2', 'maps', 'music'];
+                        files.filter(file => {
+                            const [fileName, ...path] = file.webkitRelativePath.split('/').reverse();
+                            if (fileName.startsWith('.')) return false;
+                            return path
+                                .map(folder => folder.toLocaleLowerCase())
+                                .some(folder => whitListed.includes(folder))
+                        }).reduce((uploaded, file, _ignore, queue) => {
+                            const [fileName, ...path] = file.webkitRelativePath.split('/').reverse();
+                            const [ignore, ...relativePath] = path.reverse();
+                            Module.mkdirWithParents(`${ENV.FHEROES2_DATA}/${relativePath.join('/')}`);
+
+                            const reader = new FileReader();
+                            reader.addEventListener('error', console.error);
+                            reader.addEventListener('loadend', ({ target: { result } }) => {
+                                FS.writeFile(`${ENV.FHEROES2_DATA}/${relativePath.join('/')}/${fileName}`, new Uint8Array(result), {
+                                    encoding: 'binary'
+                                });
+                                uploaded.push(file);
+                                if (uploaded.length === queue.length) {
+                                    FS.syncfs(false, err => {
+                                        if (err) return Module.clearInput('Failed to sync FS');
+                                        document.querySelector('#uploader').style.display = 'none';
+                                        document.querySelector('#launcher').style.display = 'block';
+                                    })
+                                }
+                            });
+                            reader.readAsArrayBuffer(file);
+                            return uploaded;
+                        }, []);
+                    })
+                }
+            ],
+            clearInput: (msg = '') => {
+                document.querySelector('input[type=file]').value = null;
+                msg && alert(msg);
+            },
+            mkdirWithParents: path => {
+                const parts = path.split('/');
+                try { FS.lookupPath(parts.join('/')) }
+                catch (ignore) {
+                    parts.reduce((p, part) => {
+                        p = [...p, part];
+                        try { FS.lookupPath(p.join('/')) }
+                        catch (ignore) { FS.mkdir(p.join('/')) }
+                        return p;
+                    }, []);
+                }
+            },
+            clearPath: path => {
+                try {
+                    Object.keys(FS.lookupPath(path).node.contents).forEach(node =>
+                        (FS.stat(`${path}/${node}`).mode & S_IFMT) === S_IFDIR
+                            ? Module.clearPath(`${path}/${node}`)
+                            : FS.unlink(`${path}/${node}`));
+                    FS.rmdir(`${path}`)
+                } catch (ignore) {}
+            },
+            startGame: () => {
+                removeRunDependency('syncfs');
+                document.querySelector('#uploader').style.display = 'none';
+                document.querySelector('#launcher').style.display = 'none';
+            },
+            deleteFiles: () => {
+                if (false === confirm('Are you sure?')) return;
+                Module.clearPath(ENV.FHEROES2_DATA);
+                FS.syncfs(false, ignore => {});
+                Module.clearInput();
+                document.querySelector('#uploader').style.display = 'block';
+                document.querySelector('#launcher').style.display = 'none';
+            },
+            setStatus: status => {
+                const dlProgressRE = /(?<progress>\d+)\/(?<total>\d+)/ig;
+                if (!status || !dlProgressRE.test(status)) {
+                    if ((status ?? '').startsWith('Downloading data')) progressBar.start();
+                    return;
+                }
+                dlProgressRE.lastIndex = 0;
+                const {groups: {progress, total}} = [...status.matchAll(dlProgressRE)][0];
+                const done = Math.round(progress / total * 100);
+                progressBar.set(done);
+                if (100 === done) progressBar.end();
+            },
+            canvas
+        }
+    });
+
+    document.head.append(Object.assign(document.createElement('script'), {src: './fheroes2.js'}));
+</script>
+</body>
diff --git a/android/app/src/main/assets/instruments/README.txt b/files/timidity/instruments/README.txt
similarity index 100%
rename from android/app/src/main/assets/instruments/README.txt
rename to files/timidity/instruments/README.txt
diff --git a/android/app/src/main/assets/instruments/acpiano.pat b/files/timidity/instruments/acpiano.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/acpiano.pat
rename to files/timidity/instruments/acpiano.pat
diff --git a/android/app/src/main/assets/instruments/agogohi.pat b/files/timidity/instruments/agogohi.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/agogohi.pat
rename to files/timidity/instruments/agogohi.pat
diff --git a/android/app/src/main/assets/instruments/agogolo.pat b/files/timidity/instruments/agogolo.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/agogolo.pat
rename to files/timidity/instruments/agogolo.pat
diff --git a/android/app/src/main/assets/instruments/bassoon.pat b/files/timidity/instruments/bassoon.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/bassoon.pat
rename to files/timidity/instruments/bassoon.pat
diff --git a/android/app/src/main/assets/instruments/belltree.pat b/files/timidity/instruments/belltree.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/belltree.pat
rename to files/timidity/instruments/belltree.pat
diff --git a/android/app/src/main/assets/instruments/bongohi.pat b/files/timidity/instruments/bongohi.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/bongohi.pat
rename to files/timidity/instruments/bongohi.pat
diff --git a/android/app/src/main/assets/instruments/bongolo.pat b/files/timidity/instruments/bongolo.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/bongolo.pat
rename to files/timidity/instruments/bongolo.pat
diff --git a/android/app/src/main/assets/instruments/bowglass.pat b/files/timidity/instruments/bowglass.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/bowglass.pat
rename to files/timidity/instruments/bowglass.pat
diff --git a/android/app/src/main/assets/instruments/cabasa.pat b/files/timidity/instruments/cabasa.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cabasa.pat
rename to files/timidity/instruments/cabasa.pat
diff --git a/android/app/src/main/assets/instruments/castinet.pat b/files/timidity/instruments/castinet.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/castinet.pat
rename to files/timidity/instruments/castinet.pat
diff --git a/android/app/src/main/assets/instruments/cello.pat b/files/timidity/instruments/cello.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cello.pat
rename to files/timidity/instruments/cello.pat
diff --git a/android/app/src/main/assets/instruments/choir.pat b/files/timidity/instruments/choir.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/choir.pat
rename to files/timidity/instruments/choir.pat
diff --git a/android/app/src/main/assets/instruments/church.pat b/files/timidity/instruments/church.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/church.pat
rename to files/timidity/instruments/church.pat
diff --git a/android/app/src/main/assets/instruments/claps.pat b/files/timidity/instruments/claps.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/claps.pat
rename to files/timidity/instruments/claps.pat
diff --git a/android/app/src/main/assets/instruments/clarinet.pat b/files/timidity/instruments/clarinet.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/clarinet.pat
rename to files/timidity/instruments/clarinet.pat
diff --git a/android/app/src/main/assets/instruments/clave.pat b/files/timidity/instruments/clave.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/clave.pat
rename to files/timidity/instruments/clave.pat
diff --git a/android/app/src/main/assets/instruments/congahi1.pat b/files/timidity/instruments/congahi1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/congahi1.pat
rename to files/timidity/instruments/congahi1.pat
diff --git a/android/app/src/main/assets/instruments/congahi2.pat b/files/timidity/instruments/congahi2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/congahi2.pat
rename to files/timidity/instruments/congahi2.pat
diff --git a/android/app/src/main/assets/instruments/congalo.pat b/files/timidity/instruments/congalo.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/congalo.pat
rename to files/timidity/instruments/congalo.pat
diff --git a/android/app/src/main/assets/instruments/contraba.pat b/files/timidity/instruments/contraba.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/contraba.pat
rename to files/timidity/instruments/contraba.pat
diff --git a/android/app/src/main/assets/instruments/cowbell.pat b/files/timidity/instruments/cowbell.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cowbell.pat
rename to files/timidity/instruments/cowbell.pat
diff --git a/android/app/src/main/assets/instruments/cuica1.pat b/files/timidity/instruments/cuica1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cuica1.pat
rename to files/timidity/instruments/cuica1.pat
diff --git a/android/app/src/main/assets/instruments/cuica2.pat b/files/timidity/instruments/cuica2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cuica2.pat
rename to files/timidity/instruments/cuica2.pat
diff --git a/android/app/src/main/assets/instruments/cymbell.pat b/files/timidity/instruments/cymbell.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymbell.pat
rename to files/timidity/instruments/cymbell.pat
diff --git a/android/app/src/main/assets/instruments/cymchina.pat b/files/timidity/instruments/cymchina.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymchina.pat
rename to files/timidity/instruments/cymchina.pat
diff --git a/android/app/src/main/assets/instruments/cymcrsh1.pat b/files/timidity/instruments/cymcrsh1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymcrsh1.pat
rename to files/timidity/instruments/cymcrsh1.pat
diff --git a/android/app/src/main/assets/instruments/cymcrsh2.pat b/files/timidity/instruments/cymcrsh2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymcrsh2.pat
rename to files/timidity/instruments/cymcrsh2.pat
diff --git a/android/app/src/main/assets/instruments/cymride1.pat b/files/timidity/instruments/cymride1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymride1.pat
rename to files/timidity/instruments/cymride1.pat
diff --git a/android/app/src/main/assets/instruments/cymride2.pat b/files/timidity/instruments/cymride2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymride2.pat
rename to files/timidity/instruments/cymride2.pat
diff --git a/android/app/src/main/assets/instruments/cymsplsh.pat b/files/timidity/instruments/cymsplsh.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/cymsplsh.pat
rename to files/timidity/instruments/cymsplsh.pat
diff --git a/android/app/src/main/assets/instruments/englhorn.pat b/files/timidity/instruments/englhorn.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/englhorn.pat
rename to files/timidity/instruments/englhorn.pat
diff --git a/android/app/src/main/assets/instruments/flute.pat b/files/timidity/instruments/flute.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/flute.pat
rename to files/timidity/instruments/flute.pat
diff --git a/android/app/src/main/assets/instruments/frenchrn.pat b/files/timidity/instruments/frenchrn.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/frenchrn.pat
rename to files/timidity/instruments/frenchrn.pat
diff --git a/android/app/src/main/assets/instruments/guiro1.pat b/files/timidity/instruments/guiro1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/guiro1.pat
rename to files/timidity/instruments/guiro1.pat
diff --git a/android/app/src/main/assets/instruments/guiro2.pat b/files/timidity/instruments/guiro2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/guiro2.pat
rename to files/timidity/instruments/guiro2.pat
diff --git a/android/app/src/main/assets/instruments/harp.pat b/files/timidity/instruments/harp.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/harp.pat
rename to files/timidity/instruments/harp.pat
diff --git a/android/app/src/main/assets/instruments/highq.pat b/files/timidity/instruments/highq.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/highq.pat
rename to files/timidity/instruments/highq.pat
diff --git a/android/app/src/main/assets/instruments/hihatcl.pat b/files/timidity/instruments/hihatcl.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/hihatcl.pat
rename to files/timidity/instruments/hihatcl.pat
diff --git a/android/app/src/main/assets/instruments/hihatop.pat b/files/timidity/instruments/hihatop.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/hihatop.pat
rename to files/timidity/instruments/hihatop.pat
diff --git a/android/app/src/main/assets/instruments/hihatpd.pat b/files/timidity/instruments/hihatpd.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/hihatpd.pat
rename to files/timidity/instruments/hihatpd.pat
diff --git a/android/app/src/main/assets/instruments/hrpschrd.pat b/files/timidity/instruments/hrpschrd.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/hrpschrd.pat
rename to files/timidity/instruments/hrpschrd.pat
diff --git a/android/app/src/main/assets/instruments/jingles.pat b/files/timidity/instruments/jingles.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/jingles.pat
rename to files/timidity/instruments/jingles.pat
diff --git a/android/app/src/main/assets/instruments/kick1.pat b/files/timidity/instruments/kick1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/kick1.pat
rename to files/timidity/instruments/kick1.pat
diff --git a/android/app/src/main/assets/instruments/kick2.pat b/files/timidity/instruments/kick2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/kick2.pat
rename to files/timidity/instruments/kick2.pat
diff --git a/android/app/src/main/assets/instruments/maracas.pat b/files/timidity/instruments/maracas.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/maracas.pat
rename to files/timidity/instruments/maracas.pat
diff --git a/android/app/src/main/assets/instruments/marcato.pat b/files/timidity/instruments/marcato.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/marcato.pat
rename to files/timidity/instruments/marcato.pat
diff --git a/android/app/src/main/assets/instruments/metbell.pat b/files/timidity/instruments/metbell.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/metbell.pat
rename to files/timidity/instruments/metbell.pat
diff --git a/android/app/src/main/assets/instruments/metclick.pat b/files/timidity/instruments/metclick.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/metclick.pat
rename to files/timidity/instruments/metclick.pat
diff --git a/android/app/src/main/assets/instruments/nyguitar.pat b/files/timidity/instruments/nyguitar.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/nyguitar.pat
rename to files/timidity/instruments/nyguitar.pat
diff --git a/android/app/src/main/assets/instruments/oboe.pat b/files/timidity/instruments/oboe.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/oboe.pat
rename to files/timidity/instruments/oboe.pat
diff --git a/android/app/src/main/assets/instruments/piccolo.pat b/files/timidity/instruments/piccolo.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/piccolo.pat
rename to files/timidity/instruments/piccolo.pat
diff --git a/android/app/src/main/assets/instruments/pizzcato.pat b/files/timidity/instruments/pizzcato.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/pizzcato.pat
rename to files/timidity/instruments/pizzcato.pat
diff --git a/android/app/src/main/assets/instruments/scratch1.pat b/files/timidity/instruments/scratch1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/scratch1.pat
rename to files/timidity/instruments/scratch1.pat
diff --git a/android/app/src/main/assets/instruments/scratch2.pat b/files/timidity/instruments/scratch2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/scratch2.pat
rename to files/timidity/instruments/scratch2.pat
diff --git a/android/app/src/main/assets/instruments/shaker.pat b/files/timidity/instruments/shaker.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/shaker.pat
rename to files/timidity/instruments/shaker.pat
diff --git a/android/app/src/main/assets/instruments/slap.pat b/files/timidity/instruments/slap.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/slap.pat
rename to files/timidity/instruments/slap.pat
diff --git a/android/app/src/main/assets/instruments/slowstr.pat b/files/timidity/instruments/slowstr.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/slowstr.pat
rename to files/timidity/instruments/slowstr.pat
diff --git a/android/app/src/main/assets/instruments/snap.pat b/files/timidity/instruments/snap.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/snap.pat
rename to files/timidity/instruments/snap.pat
diff --git a/android/app/src/main/assets/instruments/snare1.pat b/files/timidity/instruments/snare1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/snare1.pat
rename to files/timidity/instruments/snare1.pat
diff --git a/android/app/src/main/assets/instruments/snare2.pat b/files/timidity/instruments/snare2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/snare2.pat
rename to files/timidity/instruments/snare2.pat
diff --git a/android/app/src/main/assets/instruments/snarerol.pat b/files/timidity/instruments/snarerol.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/snarerol.pat
rename to files/timidity/instruments/snarerol.pat
diff --git a/android/app/src/main/assets/instruments/sqrclick.pat b/files/timidity/instruments/sqrclick.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/sqrclick.pat
rename to files/timidity/instruments/sqrclick.pat
diff --git a/android/app/src/main/assets/instruments/stickrim.pat b/files/timidity/instruments/stickrim.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/stickrim.pat
rename to files/timidity/instruments/stickrim.pat
diff --git a/android/app/src/main/assets/instruments/sticks.pat b/files/timidity/instruments/sticks.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/sticks.pat
rename to files/timidity/instruments/sticks.pat
diff --git a/android/app/src/main/assets/instruments/surdo1.pat b/files/timidity/instruments/surdo1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/surdo1.pat
rename to files/timidity/instruments/surdo1.pat
diff --git a/android/app/src/main/assets/instruments/surdo2.pat b/files/timidity/instruments/surdo2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/surdo2.pat
rename to files/timidity/instruments/surdo2.pat
diff --git a/android/app/src/main/assets/instruments/synstr2.pat b/files/timidity/instruments/synstr2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/synstr2.pat
rename to files/timidity/instruments/synstr2.pat
diff --git a/android/app/src/main/assets/instruments/taiko.pat b/files/timidity/instruments/taiko.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/taiko.pat
rename to files/timidity/instruments/taiko.pat
diff --git a/android/app/src/main/assets/instruments/tamborin.pat b/files/timidity/instruments/tamborin.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tamborin.pat
rename to files/timidity/instruments/tamborin.pat
diff --git a/android/app/src/main/assets/instruments/timbaleh.pat b/files/timidity/instruments/timbaleh.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/timbaleh.pat
rename to files/timidity/instruments/timbaleh.pat
diff --git a/android/app/src/main/assets/instruments/timbalel.pat b/files/timidity/instruments/timbalel.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/timbalel.pat
rename to files/timidity/instruments/timbalel.pat
diff --git a/android/app/src/main/assets/instruments/timpani.pat b/files/timidity/instruments/timpani.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/timpani.pat
rename to files/timidity/instruments/timpani.pat
diff --git a/android/app/src/main/assets/instruments/tomhi1.pat b/files/timidity/instruments/tomhi1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tomhi1.pat
rename to files/timidity/instruments/tomhi1.pat
diff --git a/android/app/src/main/assets/instruments/tomhi2.pat b/files/timidity/instruments/tomhi2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tomhi2.pat
rename to files/timidity/instruments/tomhi2.pat
diff --git a/android/app/src/main/assets/instruments/tomlo1.pat b/files/timidity/instruments/tomlo1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tomlo1.pat
rename to files/timidity/instruments/tomlo1.pat
diff --git a/android/app/src/main/assets/instruments/tomlo2.pat b/files/timidity/instruments/tomlo2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tomlo2.pat
rename to files/timidity/instruments/tomlo2.pat
diff --git a/android/app/src/main/assets/instruments/tommid1.pat b/files/timidity/instruments/tommid1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tommid1.pat
rename to files/timidity/instruments/tommid1.pat
diff --git a/android/app/src/main/assets/instruments/tommid2.pat b/files/timidity/instruments/tommid2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tommid2.pat
rename to files/timidity/instruments/tommid2.pat
diff --git a/android/app/src/main/assets/instruments/tremstr.pat b/files/timidity/instruments/tremstr.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/tremstr.pat
rename to files/timidity/instruments/tremstr.pat
diff --git a/android/app/src/main/assets/instruments/triangl1.pat b/files/timidity/instruments/triangl1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/triangl1.pat
rename to files/timidity/instruments/triangl1.pat
diff --git a/android/app/src/main/assets/instruments/triangl2.pat b/files/timidity/instruments/triangl2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/triangl2.pat
rename to files/timidity/instruments/triangl2.pat
diff --git a/android/app/src/main/assets/instruments/trombone.pat b/files/timidity/instruments/trombone.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/trombone.pat
rename to files/timidity/instruments/trombone.pat
diff --git a/android/app/src/main/assets/instruments/vibslap.pat b/files/timidity/instruments/vibslap.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/vibslap.pat
rename to files/timidity/instruments/vibslap.pat
diff --git a/android/app/src/main/assets/instruments/viola.pat b/files/timidity/instruments/viola.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/viola.pat
rename to files/timidity/instruments/viola.pat
diff --git a/android/app/src/main/assets/instruments/whistle1.pat b/files/timidity/instruments/whistle1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/whistle1.pat
rename to files/timidity/instruments/whistle1.pat
diff --git a/android/app/src/main/assets/instruments/whistle2.pat b/files/timidity/instruments/whistle2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/whistle2.pat
rename to files/timidity/instruments/whistle2.pat
diff --git a/android/app/src/main/assets/instruments/woodblk1.pat b/files/timidity/instruments/woodblk1.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/woodblk1.pat
rename to files/timidity/instruments/woodblk1.pat
diff --git a/android/app/src/main/assets/instruments/woodblk2.pat b/files/timidity/instruments/woodblk2.pat
similarity index 100%
rename from android/app/src/main/assets/instruments/woodblk2.pat
rename to files/timidity/instruments/woodblk2.pat
diff --git a/android/app/src/main/assets/timidity.cfg b/files/timidity/timidity.cfg
similarity index 100%
rename from android/app/src/main/assets/timidity.cfg
rename to files/timidity/timidity.cfg
diff --git a/src/dist/Makefile b/src/dist/Makefile
index 4e1c76db630..103f1a860cc 100644
--- a/src/dist/Makefile
+++ b/src/dist/Makefile
@@ -1,6 +1,6 @@
 ###########################################################################
 #   fheroes2: https://github.com/ihhub/fheroes2                           #
-#   Copyright (C) 2021 - 2024                                             #
+#   Copyright (C) 2021 - 2025                                             #
 #                                                                         #
 #   This program is free software; you can redistribute it and/or modify  #
 #   it under the terms of the GNU General Public License as published by  #
@@ -159,7 +159,11 @@ ifndef FHEROES2_WITH_SYSTEM_SMACKER
 	$(MAKE) -C thirdparty/libsmacker CCFLAGS="$(CCFLAGS_TP)" CFLAGS="$(CFLAGS_TP)" CXXFLAGS="$(CXXFLAGS_TP)" CPPFLAGS="$(CPPFLAGS_TP)"
 endif
 	$(MAKE) -C engine
+ifeq ($(PLATFORM),emscripten)
+	$(MAKE) -C fheroes2-ems
+else
 	$(MAKE) -C fheroes2
+endif
 ifdef FHEROES2_WITH_TOOLS
 	$(MAKE) -C tools
 endif
@@ -169,5 +173,9 @@ ifndef FHEROES2_WITH_SYSTEM_SMACKER
 	$(MAKE) -C thirdparty/libsmacker clean
 endif
 	$(MAKE) -C engine clean
+ifeq ($(PLATFORM),emscripten)
+	$(MAKE) -C fheroes2-ems clean
+else
 	$(MAKE) -C fheroes2 clean
+endif
 	$(MAKE) -C tools clean
diff --git a/src/dist/Makefile.emscripten b/src/dist/Makefile.emscripten
new file mode 100644
index 00000000000..98e74871f08
--- /dev/null
+++ b/src/dist/Makefile.emscripten
@@ -0,0 +1,43 @@
+###########################################################################
+#   fheroes2: https://github.com/ihhub/fheroes2                           #
+#   Copyright (C) 2025                                                    #
+#                                                                         #
+#   This program is free software; you can redistribute it and/or modify  #
+#   it under the terms of the GNU General Public License as published by  #
+#   the Free Software Foundation; either version 2 of the License, or     #
+#   (at your option) any later version.                                   #
+#                                                                         #
+#   This program is distributed in the hope that it will be useful,       #
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of        #
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         #
+#   GNU General Public License for more details.                          #
+#                                                                         #
+#   You should have received a copy of the GNU General Public License     #
+#   along with this program; if not, write to the                         #
+#   Free Software Foundation, Inc.,                                       #
+#   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             #
+###########################################################################
+
+CCFLAGS := $(filter-out -pthread,$(CCFLAGS)) \
+	--use-port=sdl2 \
+	--use-port=sdl2_mixer \
+	--use-port=zlib \
+	-Wno-variadic-macro-arguments-omitted
+
+LDFLAGS := $(filter-out -pthread,$(LDFLAGS)) \
+	--preload-file ../../../files/data/resurrection.h2d@/files/data/resurrection.h2d \
+	--preload-file ../../../files/lang/@/files/lang/ \
+	--preload-file ../../../files/timidity/@/etc/ \
+	-sASYNCIFY \
+	-sASYNCIFY_STACK_SIZE=20480 \
+	-sENVIRONMENT=web \
+	-sINITIAL_MEMORY=128mb \
+	-sNO_DISABLE_EXCEPTION_CATCHING \
+	-sSDL2_MIXER_FORMATS=mid,mp3,ogg \
+	-sSTACK_SIZE=262144 \
+	-lidbfs.js
+
+ifdef FHEROES2_WITH_DEBUG
+CCFLAGS := $(CCFLAGS) -gsource-map
+LDFLAGS := $(LDFLAGS) -gsource-map
+endif
diff --git a/src/dist/fheroes2-ems/Makefile b/src/dist/fheroes2-ems/Makefile
new file mode 100644
index 00000000000..200a2fe3c13
--- /dev/null
+++ b/src/dist/fheroes2-ems/Makefile
@@ -0,0 +1,48 @@
+###########################################################################
+#   fheroes2: https://github.com/ihhub/fheroes2                           #
+#   Copyright (C) 2025                                                    #
+#                                                                         #
+#   This program is free software; you can redistribute it and/or modify  #
+#   it under the terms of the GNU General Public License as published by  #
+#   the Free Software Foundation; either version 2 of the License, or     #
+#   (at your option) any later version.                                   #
+#                                                                         #
+#   This program is distributed in the hope that it will be useful,       #
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of        #
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         #
+#   GNU General Public License for more details.                          #
+#                                                                         #
+#   You should have received a copy of the GNU General Public License     #
+#   along with this program; if not, write to the                         #
+#   Free Software Foundation, Inc.,                                       #
+#   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             #
+###########################################################################
+
+DEPLIBS := ../engine/libengine.a
+CCFLAGS := $(CCFLAGS) -I../../engine
+
+ifndef FHEROES2_WITH_SYSTEM_SMACKER
+DEPLIBS := $(DEPLIBS) ../thirdparty/libsmacker/libsmacker.a
+CCFLAGS := $(CCFLAGS) -I../../thirdparty/libsmacker
+endif
+
+SOURCEROOT := ../../fheroes2
+SOURCEDIRS := $(filter %/,$(wildcard $(SOURCEROOT)/*/))
+SOURCES := $(wildcard $(SOURCEROOT)/*/*.cpp)
+
+VPATH := $(SOURCEDIRS)
+
+.PHONY: all clean
+
+all: fheroes2.js
+
+fheroes2.js: $(notdir $(patsubst %.cpp, %.o, $(SOURCES))) $(DEPLIBS)
+	$(CXX) -o $@ $^ $(LIBS) $(LDFLAGS)
+
+%.o: %.cpp
+	$(CXX) -c -MD $< $(addprefix -I, $(SOURCEDIRS)) $(CCFLAGS) $(CXXFLAGS) $(CPPFLAGS)
+
+include $(wildcard *.d)
+
+clean:
+	rm -f *.d *.o fheroes2.data fheroes2.js fheroes2.wasm
diff --git a/src/engine/audio.cpp b/src/engine/audio.cpp
index f152d36e63d..731954a1ca4 100644
--- a/src/engine/audio.cpp
+++ b/src/engine/audio.cpp
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2019 - 2024                                             *
+ *   Copyright (C) 2019 - 2025                                             *
  *                                                                         *
  *   Free Heroes2 Engine: http://sourceforge.net/projects/fheroes2         *
  *   Copyright (C) 2008 by Andrey Afletdinov <fheroes2@gmail.com>          *
@@ -540,6 +540,8 @@ namespace
         // Either there is no need to resume music playback, or the resumption failed. Let's try to
         // start the playback from the beginning.
         if ( returnCode != 0 ) {
+            track->setPosition( 0 );
+
             returnCode = Mix_FadeInMusic( mus.get(), loopCount, musicFadeInMs );
 
             if ( returnCode != 0 ) {
diff --git a/src/engine/serialize.cpp b/src/engine/serialize.cpp
index d528e8b5f72..e05b777bd91 100644
--- a/src/engine/serialize.cpp
+++ b/src/engine/serialize.cpp
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2019 - 2024                                             *
+ *   Copyright (C) 2019 - 2025                                             *
  *                                                                         *
  *   Free Heroes2 Engine: http://sourceforge.net/projects/fheroes2         *
  *   Copyright (C) 2012 by Andrey Afletdinov <fheroes2@gmail.com>          *
@@ -29,6 +29,16 @@
 #include <string>
 #include <string_view>
 
+#ifdef __EMSCRIPTEN__
+#include <cstdio>
+
+#include <emscripten.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "tools.h"
+#endif
+
 #include "logging.h"
 
 namespace
@@ -622,3 +632,41 @@ std::string StreamFile::getString( const size_t size /* = 0 */ )
 
     return { buf.begin(), std::find( buf.begin(), buf.end(), 0 ) };
 }
+
+int StreamFile::closeFile( std::FILE * f )
+{
+#ifdef __EMSCRIPTEN__
+    const bool needSyncFS = [f]() {
+        static_assert( CountBits( O_WRONLY ) == 1 && CountBits( O_RDWR ) == 1 );
+
+        const int fn = fileno( f );
+        if ( fn < 0 ) {
+            ERROR_LOG( "fileno() error: " << errno )
+            return false;
+        }
+
+        const int flags = fcntl( fn, F_GETFL );
+        if ( flags < 0 ) {
+            ERROR_LOG( "fcntl() error: " << errno )
+            return false;
+        }
+
+        return ( flags & O_WRONLY ) || ( flags & O_RDWR );
+    }();
+#endif
+
+    const int res = std::fclose( f );
+
+#ifdef __EMSCRIPTEN__
+    if ( needSyncFS ) {
+        EM_ASM(
+            // The following code is not C++ code, but JavaScript code.
+            // clang-format off
+            FS.syncfs( err => err && console.warn( "FS.syncfs() error:", err ) )
+            // clang-format on
+        );
+    }
+#endif
+
+    return res;
+}
diff --git a/src/engine/serialize.h b/src/engine/serialize.h
index efc71abfb30..05883448e55 100644
--- a/src/engine/serialize.h
+++ b/src/engine/serialize.h
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2019 - 2024                                             *
+ *   Copyright (C) 2019 - 2025                                             *
  *                                                                         *
  *   Free Heroes2 Engine: http://sourceforge.net/projects/fheroes2         *
  *   Copyright (C) 2012 by Andrey Afletdinov <fheroes2@gmail.com>          *
@@ -669,7 +669,9 @@ class StreamFile final : public IStreamBase, public OStreamBase
         }
     }
 
-    std::unique_ptr<std::FILE, int ( * )( std::FILE * )> _file{ nullptr, []( std::FILE * f ) { return std::fclose( f ); } };
+    static int closeFile( std::FILE * f );
+
+    std::unique_ptr<std::FILE, int ( * )( std::FILE * )> _file{ nullptr, closeFile };
 };
 
 namespace fheroes2
diff --git a/src/engine/thread.cpp b/src/engine/thread.cpp
index 10f86736900..e396ae026fa 100644
--- a/src/engine/thread.cpp
+++ b/src/engine/thread.cpp
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2022 - 2023                                             *
+ *   Copyright (C) 2022 - 2025                                             *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
@@ -23,10 +23,39 @@
 #include <cassert>
 #include <memory>
 
+namespace
+{
+#ifdef __EMSCRIPTEN__
+    class MutexUnlocker
+    {
+    public:
+        explicit MutexUnlocker( std::mutex & mutex )
+            : _mutex( mutex )
+        {
+            _mutex.unlock();
+        }
+
+        MutexUnlocker( const MutexUnlocker & ) = delete;
+
+        ~MutexUnlocker()
+        {
+            _mutex.lock();
+        }
+
+        MutexUnlocker & operator=( const MutexUnlocker & ) = delete;
+
+    private:
+        std::mutex & _mutex;
+    };
+#endif
+}
+
 namespace MultiThreading
 {
     void AsyncManager::createWorker()
     {
+        // Emscripten has no pthread support. The worker thread should not be started.
+#ifndef __EMSCRIPTEN__
         if ( !_worker ) {
             _runFlag = true;
             _worker = std::make_unique<std::thread>( AsyncManager::_workerThread, this );
@@ -37,10 +66,15 @@ namespace MultiThreading
                 _masterNotification.wait( lock, [this] { return !_runFlag; } );
             }
         }
+#endif
     }
 
     void AsyncManager::stopWorker()
     {
+#ifdef __EMSCRIPTEN__
+        // Emscripten has no pthread support. The worker thread should not be running here.
+        assert( !_worker );
+#else
         if ( _worker ) {
             {
                 const std::scoped_lock<std::mutex> lock( _mutex );
@@ -54,13 +88,33 @@ namespace MultiThreading
             _worker->join();
             _worker.reset();
         }
+#endif
     }
 
     void AsyncManager::notifyWorker()
     {
         _runFlag = true;
 
+        // Emscripten has no pthread support, so instead of passing tasks to the worker thread, we will process them immediately in the current thread.
+#ifdef __EMSCRIPTEN__
+        assert( !_exitFlag );
+
+        while ( _runFlag ) {
+            const bool moreTasks = prepareTask();
+            if ( !moreTasks ) {
+                _runFlag = false;
+            }
+
+            {
+                // In accordance with the contract, the _mutex should NOT be acquired while calling the executeTask().
+                MutexUnlocker unlocker( _mutex );
+
+                executeTask();
+            }
+        }
+#else
         _workerNotification.notify_all();
+#endif
     }
 
     void AsyncManager::_workerThread( AsyncManager * manager )
diff --git a/src/engine/thread.h b/src/engine/thread.h
index d3f9bb00ae2..4885dea2252 100644
--- a/src/engine/thread.h
+++ b/src/engine/thread.h
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2022                                                    *
+ *   Copyright (C) 2022 - 2025                                             *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
@@ -53,11 +53,10 @@ namespace MultiThreading
         // Notify the worker thread about a new task. The _mutex should be acquired while calling this method.
         void notifyWorker();
 
-        // Prepare a task which requires mutex lock. Returns true if more tasks are available.
+        // Prepare the next task. The _mutex will be acquired while calling this method. Returns true if more tasks are available.
         virtual bool prepareTask() = 0;
 
-        // Task execution is done in non-thread safe mode! No mutex lock for any means of synchronizations are
-        // done for this call.
+        // Execute the next task. NOTE WELL: the _mutex will NOT be acquired while calling this method.
         virtual void executeTask() = 0;
 
     private:
diff --git a/src/fheroes2/game/game_hotkeys.cpp b/src/fheroes2/game/game_hotkeys.cpp
index be067217449..4df9820230e 100644
--- a/src/fheroes2/game/game_hotkeys.cpp
+++ b/src/fheroes2/game/game_hotkeys.cpp
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2019 - 2024                                             *
+ *   Copyright (C) 2019 - 2025                                             *
  *                                                                         *
  *   Free Heroes2 Engine: http://sourceforge.net/projects/fheroes2         *
  *   Copyright (C) 2010 by Andrey Afletdinov <fheroes2@gmail.com>          *
@@ -27,7 +27,6 @@
 #include <array>
 #include <cassert>
 #include <cstring>
-#include <fstream>
 #include <functional>
 #include <map>
 #include <set>
@@ -43,6 +42,7 @@
 #include "localevent.h"
 #include "logging.h"
 #include "players.h"
+#include "serialize.h"
 #include "settings.h"
 #include "system.h"
 #include "tinyconfig.h"
@@ -452,17 +452,17 @@ void Game::HotKeysLoad( const std::string & filename )
 
 void Game::HotKeySave()
 {
-    // Save the latest information into the file.
     const std::string filename = System::concatPath( System::GetConfigDirectory( "fheroes2" ), "fheroes2.key" );
 
-    std::fstream file( filename.data(), std::fstream::out | std::fstream::trunc );
-    if ( !file ) {
-        ERROR_LOG( "Unable to open hotkey settings file " << filename )
+    StreamFile fileStream;
+    if ( !fileStream.open( filename, "w" ) ) {
+        ERROR_LOG( "Unable to open the hotkey settings file " << filename )
         return;
     }
 
-    const std::string & data = getHotKeyFileContent();
-    file.write( data.data(), data.size() );
+    const std::string data = getHotKeyFileContent();
+
+    fileStream.putRaw( data.data(), data.size() );
 }
 
 void Game::globalKeyDownEvent( const fheroes2::Key key, const int32_t modifier )
diff --git a/src/fheroes2/system/settings.cpp b/src/fheroes2/system/settings.cpp
index 20d5e9636ed..2b822b6365a 100644
--- a/src/fheroes2/system/settings.cpp
+++ b/src/fheroes2/system/settings.cpp
@@ -1,6 +1,6 @@
 /***************************************************************************
  *   fheroes2: https://github.com/ihhub/fheroes2                           *
- *   Copyright (C) 2019 - 2024                                             *
+ *   Copyright (C) 2019 - 2025                                             *
  *                                                                         *
  *   Free Heroes2 Engine: http://sourceforge.net/projects/fheroes2         *
  *   Copyright (C) 2009 by Andrey Afletdinov <fheroes2@gmail.com>          *
@@ -23,7 +23,6 @@
 
 #include <algorithm>
 #include <cstdlib>
-#include <fstream>
 #include <sstream>
 #include <utility>
 
@@ -348,16 +347,14 @@ bool Settings::Save( const std::string_view fileName ) const
         return false;
     }
 
-    const std::string cfgFilename = System::concatPath( System::GetConfigDirectory( "fheroes2" ), fileName );
-
-    std::fstream file;
-    file.open( cfgFilename.data(), std::fstream::out | std::fstream::trunc );
-    if ( !file ) {
+    StreamFile fileStream;
+    if ( !fileStream.open( System::concatPath( System::GetConfigDirectory( "fheroes2" ), fileName ), "w" ) ) {
         return false;
     }
 
-    const std::string & data = String();
-    file.write( data.data(), data.size() );
+    const std::string data = String();
+
+    fileStream.putRaw( data.data(), data.size() );
 
     return true;
 }