In this puzzle game with an extremely small resolution (upscaled) you have to collect all the green blocks with the blue block. However, there are many obstacles between you and your goal in the 40 levels, such as the red enemies which can move each time you move and make you restart the level on contact.
Use the arrow keys to move and R to restart a level. Press M to (un)mute music, and S to (un)mute sound effects. Your progress is automatically saved after completing each level, but you can use Ctrl+Alt+Shift+R if you want to restart. If you really want to skip a level, you can use Ctrl+Alt+Shift+S.
Be warned this Puzzle game is hard.