Use arrow keys to move, "[" to shoot, "]" to drop bombs. The keys can be custom in Options Menu.
Play Gun Mayhem on Cool Maths Games Online : Gun Mayhem is a fighting game, support multiplayer up to 4 players at once. Select your character, customize weapon and clothes, and shoot the opponents to clear level. You can try the weapons in Test Weapon Room. Try to beat your opponent to unlock new weapons and new maps. Good Luck !