The player controls a small, circular spaceship which must travel around the screen collecting crystals. This task is made more difficult by the aliens which constantly swarm out from the portals on both sides of the screen. These can be shot down by the ship's gun (which has unlimited ammo) or eliminated by activating one of the player's limited supply of "smart bombs", which will clear the screen of all current enemies.

The player controls a small, circular spaceship which must travel around the screen collecting crystals. This task is made more difficult by the aliens which constantly swarm out from the portals on both sides of the screen. These can be shot down by the ship's gun (which has unlimited ammo) or eliminated by activating one of the player's limited supply of "smart bombs", which will clear the screen of all current enemies.