The player is taken to the outer edges of the galaxy, and their mission is to protect Alpha IV from alien ships who are attacking it. The game can be played up to five levels, and the higher the level, the more ships players have to destroy. The ships vary in their size, speed, and destructive capability. Not only do they attack Alpha IV, but they also attack your weapons pod, so the point is to wipe them out before they have a chance to attack.

Missiles are fired at the ships from the weapons pod which rotate through 360 degrees. The control panel shows where the attacking ship is, leaving the player to find it and destroy it. Only one ship attacks at any time and it continues to attack until the ship is either destroyed or the time limit expires. If the 'Turrent Damaged' message appears, traversing will be slow until the self repair systems fixes the damage, giving the ships more chance to continue their attack on Alpha IV.

If all the ships have been wiped out, the player is returned to the title screen to select a new game. On harder levels, missiles that come from alien ships have a disturbing frequency and precision.