There three main characters in the game viz. the shooter, the good ball and the evil balls.
The shooter keeps firing bullets continuously, but you can control the movement and the direction of the shooter using the joystick.
Your main motive is to protect the good ball from getting hit by your bullets.
The game totally revolves around the health of the good ball & if the health bar drops down to zero then the game ends.
In the due course of the game there will be a lot of evil balls spawning at random.
Your next motive is to shoot these evil balls and earn points.
In a Nutshell, you have to shoot the evil balls, but take care not to hit the good ball and preserve it's health so that you can earn more points.