If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
In this game you're a soccer player who runs towards the opponent's goal. Defenders will try to stop you. You need to avoid them. When you get close to the goal you'll need to shoot.
W / Up Arrow Key - Jump.
S / Down Arrow Key - Roll.
A / Left Arrow Key - Slow Down.
Spacebar - Shoot.