Your task is to kill as many monsters as possible. In the first level you must shoot at least 6 monsters, in the second 11, in the third 15, and in the fourth 22 monsters. In each level you should not miss more than three monsters, otherwise the game will be over.
Use the mouse to aim and click to shoot.
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.