Use WASD to move cat and up and down arrow keys to move cannon up or down. Press space to shoot basketball at cat. Too many basketballs at once can cause lag. The cannon player is trying to shoot the cat player 10 times and the cat player is trying to evade the cannonballs/basketballs. The time the cat player survives is his/her/its score.
My friend Toby gave me the basketball idea, and I had already done 2 battle games like this. I also have two "cat cannon" projects