Cheat Machines: Game Genie and Action Replay on the Game Boy

There was a particular thrill, in the school playground of the 1990s, to knowing the right code. Punch in a string of letters and numbers, and a game that had beaten you for weeks would suddenly hand you infinite lives. The devices that made this magic possible were the cheat cartridges.

On the Game Boy, two names ruled this grey area: the Game Genie and Action Replay.

The Game Boy Game Genie

The Game Genie was the work of the British studio Codemasters, sold in North America by Galoob and elsewhere by Camerica. You slotted your game into the Game Genie, then slotted the Game Genie into the Game Boy. On power-up, a menu let you type in alphanumeric codes, which the device used to alter the data passing between the cartridge and the console, effectively reprogramming the game on the fly. A couple of face buttons let you switch codes on and off or jump back to the code screen.

The most famous Game Boy Cheat device: Game Genie

The Lawsuit That Made Cheating Legal

Nintendo hated these devices and took the fight to court. In the early 1990s it sued Galoob over the Game Genie, arguing that altering a game created an unauthorised derivative work. Nintendo lost. A US court ruled that the Game Genie simply changed how a game played for the owner's own enjoyment, much like fast-forwarding a film, and broke no copyright. That verdict effectively made cheat devices legal and opened the door for everyone that followed.

Action Replay and the Cheat Wars

The Game Genie was not alone. Datel's Action Replay did much the same job and sat at the head of a whole family of rival brands such as GameShark and Code Breaker. There was a real technical split between them: where the Game Genie patched the data coming off the cartridge, devices like the Action Replay and GameShark worked on the console's memory directly, continuously forcing values such as lives or health to stay where you wanted them. That let them do tricks the Game Genie could not, including hunting for brand-new codes on the device itself. For players, the choice often came down to which code lists you could get hold of in magazines and on early websites.

Game Boy Cheat Device: Action Replay Pro

Reprogramming on the Fly

What made these devices clever was the pass-through trick. By sitting between the cartridge and the Game Boy, they could intercept and tweak small pieces of data as the game ran, changing values like lives, health or starting level without ever touching the cartridge permanently. Whole communities sprang up around finding and sharing new codes, and magazines devoted pages to them. It was an early, grass-roots form of game modding.

Why Game Boy Cheat Devices Are Collectible

Although they were unlicensed and a little mischievous, the Game Boy Game Genie and its rivals are now nostalgic icons in their own right, often remembered as fondly as the games they bent. Complete examples with their chunky code books are a fun, characterful addition to a collection. The cartridge slot turned out to be full of these hidden tricks: the cheat and memory modules are catalogued in Hidden Powers, Part 5, or explore more peripherals in the Knowledge Base.