when you press 'a', shark will go back, when you press 's', shark will go down, when you press 'd', shark will go forward, when you press 'w' shark will going to up, when you press 'e', shark will disappear 5 second. when you eat the heart, you will get a lot of score. when you have a 25 score, you will win the game. when you press space bar, shark will shot the star. you can remove the ball. when the ball touch the shark, you will lose score.
