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 brain washing gas which earthlings are especially susceptible to. Knowing this you realise your only hope for survival is to shoot them whilst they are still in the sky.
THE CONTROLS FOR THE SHIP ARE AS FOLLOWS
Z - LEFT X -RIGHT and M TO FIRE
RUN is the keyword to start the game so if you are overrun you will have to type this followed by ENTER to play again.
MAY THE FORCE OF TITAN BE WITH YOU.
To load Ace Invasion, which fits into the standard, unexpanded, Jupiter Ace, follow the steps summarised below.