Mixed in with the meteors are white spinning bombs. While letting a meteor get past you will only lower your score, you have to shoot the spinners. If one gets past, you will lose a life. On the more difficult levels, ufo's and guided missiles will also appear occasionally and attempt to destroy your canon.
If you become trapped in a hopeless situation, your canon can enter hyperspace and be instantly transported to a different location on the screen. Just be careful, sometimes you may be transported to a situation worse than the one you left! The game ends when all of your laser canons have been destroyed.