The Ultra are an evil race of mutant aliens and in this game they invite the player to a challenge in outer space. The game is a fixed-screen shoot 'em up that consists of 16 levels. Each level has its own type of enemies with its own movement pattern. Like in other shooters the player's controls are limited to moving left and right along the bottom of the screen and blasting away at the aliens above. Too much shooting leads the weapon to overheat and the player has to wait for it to cool down. The objective is simple: to clear the whole screen and then advance to the next level. For each of the first eight levels the points increase starting with ten in the first and twenty in the second. At 2,000 and 10,000 points bonus lives are awarded. When starting out the player has five lives.

This game was also ported over to the MSX and the Memotech MTX in 1984, as well as the Tatung Einstein in 1985. However the name of the game was changed to Maxima on those systems.