Kinda hard to explain - this was a pseudo-3D Tetris style game.
We have a sort of 3D cube (it's really just 7 layers stacked on top of one another).
A shape made up of a number of cubes will appear towards the bottom of the cube, the shape will be made up of one, two or 3 cubes in a specific configuration.
Initially, this shape will be red in color, after a second it'll turn amber then after another second it'll turn green and 'lock' into place. Before the shape locks we can move it either up, down, left or right to position it, but we cannot rotate the shape!
Once the shape has 'locked' it will begin to rise towards the top of the cube where it will finally land and rest on the top layer, you can press the down arrow key to cause the shape to move up quicker.
The main object is to connect 7 cubes in a row either horizontally or vertically, if we get 7 cubes in a row that line will disappear and we'll get some points.
If any of the cubes that make up the shape clashes with any of the cubes already landed on the top layer then those cubes are annihilated and you lose one of your lives.
Remember - you can't rotate the shapes before they lock, you can only move them up, down, left or right - however, you can rotate the top layer of the cube only once the shape has locked into place and begins to rise towards the top of the cube - simply use the left and right arrow keys to rotate the top layer of the cube as the shape rises.
This means each time a new shape appears you have 3 seconds to consider where to position the shape and also how you intend to rotate the top layer of the cube to avoid clashes and connect the cubes and annihilate lines.
Honestly - it's not that complicated and my explaination of how to play probably makes it more confusing, it's fairly intuitive after a few minutes of playing around, actually kinda fun!