Invasion Orion is a 1979 science fiction strategy game written and published by Automated Simulations (who would become Epyx in 1983). It was a single- or two-player sequel to the original two-player Starfleet Orion, which had been published late in 1978. The game was originally written in BASIC for the Commodore PET and TRS-80, but later ported to other early home computer platforms including the Atari 8-bit family, and Apple II. This package actually contains both the Apple II and TRS-80 versions on a flippy disk.
After Starfleet Orion had been completed the authors, Jon Freeman and Jim Connelly, decided that the original placed too many demands on the players. In the case of the cassette versions, for instance, the player would first have to type in a series of complex inputs to the "BUILDER" program and save them to a separate cassette, then load up the game and use it to load in the scenario that had been saved to the other cassette. Additionally, the game demanded two players who had to take turns typing in their commands on the keyboard, hopefully not peeking to see what the other user was entering. Finding two players willing to play a longish strategy game was always difficult – the final pre-rolled mission had a suggested playing time of six hours.
Both Freeman and Connelly were interested in a new game with what they called "solo play", a single player against a computer opponent. Given the limited resources of the Commodore PET the game was written on, any sort of strategy on the computer's part would have to be simple. In order to make up for this and have some sort of challenge, they made the scenarios somewhat "one sided", allowing the computer AI to simply charge in and attack with some hope of winning.