Game Genie

The Game Genie was a line of video game accessories that allowed players to alter codes transmitted between game cartridges and a video game console, known informally as a cheat cartridge. Developed by Codemasters and distributed by Galoob in the U.S. and Camerica in Canada, it debuted in 1990 for the Nintendo Entertainment System (NES), with later versions for the Super NES, Game Boy, Sega Genesis, and Game Gear.

The device was central to the 1992 landmark case Lewis Galoob Toys, Inc. v. Nintendo of America, Inc., where the court ruled that Game Genie did not infringe on Nintendo’s copyrights, as it did not create a permanent derivative work or impact game sales. The decision helped establish reverse engineering as fair use in the United States.

Despite selling five million units worldwide, plans for a "Game Genie 2" never materialized, and no versions were made for later consoles. Similar devices, such as Action Replay, Code Breaker and GameShark, later filled its role.