So far I've only finished the physics of this game, but I think they turned out pretty well! I don't know what kind of characters there should be expect they must have big round heads and no / tiny hands. You can try the game with your friend using the same keyboard.
INSTRUCTIONS:Pass the ball by pressing your up key. Jump to bounce the ball with your head so it goes on the other side of the net. If you touch the ball more than 3 times it is a fault. If you let the ball fall on your side of the net it is a fault.