How did Game Genie work?

GG works by changing variables. So for instance let’s take MegaMan when you have a game of MegaMan there might be a variable called CUT_BLADE. And the game starts out with CUT_BLADE=0 meaning you don’t have it. When you defeat Cut Man the game changes the varible to CUT_BLADE=1 which means you have and can use the cut blade. GG works by simply changing the number. Now the variables aren’t all named so obviously so we don’t know which one controls which weapon so could guess and such.

So there are lot of variable in games. There might be a number which controls how many fireballs Mario can have on screen which is 3 and never changes but with GG you might be able to change it to 15 and be all powerful. There might be a variable for how fast Toad moves in SMB2 you might be able to double his speed.

When you’re developing a game it’s very annoying to die all the time when you’re testing the level. So if you want to put a secret cliff at the very limit of a jump you might create a mode so the game doesn’t let you die. These modes often remain in the game just turned off so with a GG you might be able to acces the ‘debug mode’ and be able to do things like become invincible. fly in game that don’t allow flying, warp to specific levels.

To follow up on rrmkdynuupye, the “codes” that one would enter into Game Genie were actually hexadecimal (base sixteen) addresses of where in the game’s memory those variables were stored, followed by the new value to be written in/over.

Sometimes though, like on the Sega Game Gear, the only way to do this was to actually impose the game-genie between the game cartridge and the the system itself, and physically fake “being the cartridge.”

These kind of “exploitative” cheating methods were actually vigorously pursued in court by Nintendo and the like.

Nowadays most cheat codes are actually designed into the game as a feature, but in a way that entering them keeps you from, say, making the high score list.

1. Attach game genie to the end of NES cartridge
2. Insert cartridge with attached game genie into NES
3. Input desired codes
4. Enjoy infinite lives in Marble Madness

@Ansible1 FFFFUUUUUU MARBLE MADNESS!!!!

I think RRMKDYNUUPYE is a game genie code.

Marble Madness on Commodore 64 = win

Ug, those stupid slinkies that ate the marbles.

or the steelies.

I had GG codes that made Street Fighter II do all kinds of crazy things, like allowing you jump off the walls, add blood and other, non-number related things. How did Game Genie do that, smart guys?

@drdoombot

Well, Street Fighter II was never a NES game, so what you had was probably different.

Yes, but SNES had a Game Genie as well, which attached to the cartridge in the same way.

Remember how Chun Li and Vega jumped off the wall? I that was a variable for ever character.

@drdoombot

By that time I’m sure it had advanced technologically.