Rocks'n'Lasers is an old style puzzle game. It's designed to be challenging. Although the number of levels might not seem that large at first, they are thought through and complex enough to provide hours of fun. Once you solve them all perfectly, there's also the map editor.
A context menu should be shown when right-clicking or, on touch devices, long-pressing in the game. This menu especially allows to play in full screen and control the volume.