I'm couldn't think of a name for this game... Use the arrow keys to move the red square. Use W, A, S, and D to move the blue square. How the CPU works: It finds a random square that is not its color. Then it moves to that square. If there are less than 50 gray squares left, it will only target gray squares.
Added CPU-only Yellow and Green. Look out! Green will follow the nearest player. Yellow is super fast, but takes a second to choose a new square. Oh man, it's so optimized that the 4p games last about 20 seconds. Gonna slow everyone down in 4p.