If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Your goal in this particular game is to shoot on the goal precisely and score! But to be able to achieve that, you will have to select the angle and the velocity of the kick that will follow. So, to have influence on these two parameters, you need to know that the controls are place on the mouse.
So, try to be better than the goalkeeper by shooting and scoring precisely! Enjoy these football kicks in space!