Arrow keys for player 1, awsd keys for player 2. If you want to play by yourself, enable CPU by typing 1 in the 1 or 2 player box, and CPU will be activated. CPU is pretty hard to beat though. Blue scores points in the red goal, red scores in blue.
MINOR GLITCH: If you press the flag, there is a chance that player 2 (Red) will glitch and immediately start scoring goals. Re-click the flag to fix this.