Some games could be particularly brutal with their difficulty, and when the developer didn't enable any kind of help, the only option for players was to adopt an external cheat system. The three main names on the market were Action Replay, GameShark, and the Game Genie, so reviled by Nintendo that it even sued one of its original distributors. Today we're going to take a close look at how the Game Genie worked, and to be honest, it's much more complicated than we imagined…
There is an old phrase used to describe the difficulty of classic games, and it's "Nintendo Hard". Battletoads, the first Contra without Konami codes, Castlevania, Ghosts 'n Goblins, Ninja Gaiden, Mega Man, TMNT, Punch-Out!... relentless titles if there ever were any. The idea was that the player would always come back for more, but in many cases the frustration grew so great that they were left half-finished. Of course... taking difficulty to the maximum wasn't exclusive to Nintendo.
The rest of the platforms weren't far behind, and the quest for cheats was constant. Let's be honest: most video game publications in the '80s and '90s existed to share tricks, cheats, and shortcuts. However, that took on another dimension with the launch of 'cheat systems', among which the Game Genie stands out.
How the Game Genie worked
The video explains all the technical details about the interaction between the Game Genie and the different platforms it was released for. Essential characteristics such as the console's processor and the use of 'bank switching' radically changed how it worked, but in relaxed terms we can say that the Game Genie is a 'man in the middle' that intercepts communication between the cartridge ROM and the console.
All the player had to do was enter a special code to modify a couple of bytes linked to an element within the game, for example, the number of available lives or the remaining time. When the processor needs to execute or read something from the ROM, the value inside the cartridge is stored in an internal register. The Game Genie's job is to monitor every ROM read, and if one of the codes affects a memory location, it 'hijacks' the signal to replace it with another value.
This technique means a code can only read and/or modify one memory area at a time, therefore the Game Genie accepted between three and five codes at most. 'Bank switching' complicates things even further, because in the 'swapping' process, an identical memory address doesn't always correspond to the same ROM value. The Game Genie had no way of knowing which ROM bank had been mapped into memory, and its partial solution was to add an extra comparison value (or integrity check) to the code.
The Game Genie was available for NES, Game Boy, Sega Game Gear, Super Nintendo and Genesis/Mega Drive. Many players still believe that Action Replay and GameShark are superior options (creating your own codes didn't give so many headaches), but any cheat was welcome back then, regardless of the system used.
