(#150) Docs: add a screenshot

Author: ForNeVeR

O21.sln

@@ -25,6 +25,8 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "docs", "docs", "{ED5D37B9-3F2A-4C8C-9625-B6FA1152AF02}"
 	ProjectSection(SolutionItems) = preProject
 		docs\resources.md = docs\resources.md
+		docs\screenshot.png = docs\screenshot.png
+		docs\screenshot.png.license = docs\screenshot.png.license
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".config", ".config", "{58DB85EB-D5FC-4D30-9FC7-BDD95AFE31EB}"

README.md

@@ -11,11 +11,13 @@ O21 is a modern free and open-source remake of [U95][old-games.u95], a game by [
 
 Implementation Status
 ---------------------
-
 Some of the game engine features have been implemented, but the game is not in a playable state.
 
 Visit [the issue tracker][issues] if you want to know more.
 
+The screenshot of the currently implemented version (mind that not every element from the screenshot might be functional yet):
+![Screenshot][screenshot]
+
 Usage
 -----
 
@@ -81,6 +83,7 @@ Acknowledgments
 [old-games.u95]: https://www.old-games.ru/game/4676.html
 [open-sage]: https://github.com/OpenSAGE/OpenSAGE
 [reuse.spec]: https://reuse.software/spec-3.2/
+[screenshot]: docs/screenshot.png
 [status-enfer]: https://img.shields.io/badge/status-enfer-orange.svg
 [wikipedia.o21]: https://en.wikipedia.org/wiki/HNLMS_O_21
 [wikipedia.u-95]: https://en.wikipedia.org/wiki/German_submarine_U-95_(1940)

docs/screenshot.png

@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2024 O21 contributors <https://github.com/ForNeVeR/O21>
+
+SPDX-License-Identifier: MIT