Atari 2600- Demon Attack (atarionline.org)
Demon Attack is a game for the Atari 2600 developed by Imagic in 1982. Although it is said to be inspired by the 1979 arcade game Galaxian, its gameplay and visuals are more closely related to some waves from the 1980 arcade game Phoenix. This similarity led to a lawsuit from Atari, Inc., who had acquired the home video game rights to Phoenix. The dispute was eventually settled out of court, and despite the legal challenge, Demon Attack went on to become Imagic’s best-selling game as of 1983.