Ace Invasion

On a fact-finding tour of Jupiter in the 23rd century you have discovered the planet being invaded by aliens and they need to be stopped. The aliens have the ability to land on a planet to take over it with their brainwashing gas so you must keep blasting them to stop them landing on the surface. Ace Invasion is a side view single screen shooter where you control a spacecraft at the bottom of the screen, moving left or right, to blast aliens that appear from the top of the screen moving downwards. The aliens appear one at a time and must be blasted before they land on the bottom of the screen or it is game over.