When you start the game, you will have 90 seconds to score as many points as you can. The blue character (or the one on the right) uses the arrow keys to move. The red character (or the one on the left) uses the wasd keys to move. Whoever has the most points when the timer runs out wins!
Also, just a heads up. Sometimes when you start the game, the ball glitches and you can't kick it. If that happens, just reclick the flag.