Battle a never-ending wave of invading alien vessels with your Galactic Gladiator, a ship stationed at the bottom of the screen, which can move laterally and fight off the attackers with its Zap Ray. The aliens will attempt to zap you right back with their own rays, and must be destroyed for points, the Zap Ray can be fired continuously, but if it heats up too much your ship will be destroyed. At the very top hovers the mothership: difficult to dodge, but worth quite a lot if repeated hits are scored.

6 difficulty levels are available, and the game keeps track of the best score for each level - as well as a separate record for each player's personal best.