When is a Space Invaders rip-off not a Space Invaders rip-off? When it also rips off Galaxian and Gyruss!
No, that’s unfair to poor old Gorf, an arcade game by Bally Midway that was ported to Atari 8-Bit by Roklan Software. Gorf is an entertaining and enjoyable game in its own right that most certainly has its own identity — albeit perhaps not what was originally intended.
This began life as an adaptation of Star Trek: The Motion Picture, of all things, but was presumably adapted into what it eventually became after someone at Bally Midway figured that a game involving a 20-minute sequence slowly panning around a spaceship with nothing happening probably wouldn’t be that much fun. The end product was rather good… and bastard hard.