A somewhat primitive albeit fun fixed screen shooter loosely inspired by Space Invaders for the Jupter Ace. Whilst on a fact finding tour of Jupiter (where else!), sometime in the twenty-third century, you look up in horror to see the planet being invaded by mutant aliens. From previous research you know that they are the type of mutants that have only to land on a planet to take it over, as they shed a deadly brainwashing gas which earthlings are especially susceptible to. Knowing this, you realize your only hope for survival is to shoot them whilst they are still in the sky.