Use your great reflexes and defend your pulsating star from incoming asteroids. The more asteroids you destroy, the more return. Strategize your use of impulses and try to avoid being hit in order to survive longer.
Tap or click in the direction of incoming asteroids to send pulses in their direction.
The longer you wait in between pulses sent out, the larger your pulse will grow. Larger pulses can take out multiple asteroids at once.