"Qubus" is a game where two players try to beat each other by throwing cubes. If your avatar gets hit by a cube it will lose health. If a red cube touches another red cube more red cubes will spawn around them. There are also health-points to collect and black cubes which protect you against the red ones. You can build barricades or fortresses with them.

Player 1: move with W A S D, pick a cube with "G" also put it back with "G" and throw it with "H"
Player 2: move with arrow-keys, pick and put back a cube with "0" and throw it with "delete"