Don't know why, but you must click the green flag a few times to play it without the game breaking. P1: wasd P2: arrows P1: Black (Top Screen) P2: White (Bottom Screen) All you do is walk around. Thats it.
Just a little experimentation with multiplayer split screen. When your both in the same room, it will appear that both players are in the same room, but in a mirror display. So P1's exact coordinates is opposite for P2, but a little off :P You will see what I mean when you go touch the brown square (door). Enjoy! And feel free to remix!