Galax Attax is a clone of Namco's Galaxian, which was one of the first shoot'em'ups to deviate from the original Space Invaders fare in favor of things such as aliens with individual behavior and movement.
Your goal: Shoot down all the aliens as they fly in formation. If they break free from their formation and fly at you, they are worth twice as many points, while also being more dangerous.
On the Tandy computer, the game uses NTSC artifacting for colour on a black space backdrop, whereas the Dragon version has been reprogrammed with a white backdrop, which makes the orange bullets harder to see, resulting in an overall more difficult game. The Tandy version was later reprogrammed with new sprites which looked more like the insect-themed ones from the original Galaxian instead of the more abstract ones of the first version.