There two rotating colored circles (red and blue) at the center of the screen and you have to shoot the colored ball given to you at the right time so it hits the central circle of the same color. If you hit the circle with wrong color, you will lose. Also you have a very limited time to shoot the ball and you will lose if you run out of time. Also the direction that you have to shoot the colored ball changes randomly which makes your work even more difficult! Your final score is based on the number of times that you were able to shoot and hit the ball correctly.