You have volunteered for hazardous duty in Sector Alpha, a remote part of the Earth's Galactic Alliance. You know that it would be tough and that perhaps you would not return. But someone has to defend the perimeters against the robot Penetrators from the alien Throgg Empire! Besides, the pay is great, assuming you survive to collect.

The object of this game is to successfully destroy all the robot Penetrator ships as quickly as possible while avoiding their torpedo missiles. Does this sound too simple? Well the catch is, you're being attacked in three dimensions. Missiles come at you from all directions. You will have to monitor all 360 degrees with your radar screens while rapidly rotating your ship across a scrolling panoramic landscape! We hope you survive.