Esc - Pause/Game Options.
Press the arrows in the order shown before time runs out to avoid the bull's rush. The more quickly you click them, the more fame you get. When your fame meter is full, you can move on to the next level.
In later levels you can upload wacky pics of your friends (or use preselected pics) as the bull's face for extra fun!
If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).