A simplified game of Billiards, or Pool as it's also known. You must all the red balls before the time runs out, don't sink the white, or you'll be penalised for time, run out of time, and it's game over! Noooo!
Use the mouse to aim, and click to shoot, the further from the white ball your mouse is, the harder the shot.
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.