Instructions are provided in game. The basic concept is that you have to kill as many enemies as possible, but you can't do it using your own body alone, as you're not strong enough! Press Spacebar to take over other people's bodies to keep fighting, and don't stop until you can't fight no more!

Known issues: If you miss taking over somebody's body, you'll need to restart the game!
*Punching animation won't show sometimes
*Enemies will punch each other
*If an enemy if above you, he will think you're at the same Y position as him