If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
In this game you have to get away with all your little shenanigans without the teacher spotting you. Each shenanigan you get away with will earn you a different score. Be careful though as you never know when the teacher might turn around and catch you doing something you shouldnt be doing. This game is great fun but does need you to pay attention to whats going on!