There was this NES game called "The Magic of Scheherazade" that had what at first looked like a very complex password system, but even as a kid, I was able to figure out how to exploit it to cheat at the game, giving me lots of money or start at higher levels, as it wasn't actually hashed very well.
The game itself is kind of obscure and looks like it's a cheap ripoff of Legend of Zelda (there are several scenes that are actually blatant rips), but it's got a lot of depth and is a lot of fun, even today. There's both over-world-action- and turn-based combat, and a whole time travel component.
IIRC, the password system was so bad that you could create game-puzzle-breaking states with it, to where you were in certain levels without items that you needed to progress.
The game itself is kind of obscure and looks like it's a cheap ripoff of Legend of Zelda (there are several scenes that are actually blatant rips), but it's got a lot of depth and is a lot of fun, even today. There's both over-world-action- and turn-based combat, and a whole time travel component.
IIRC, the password system was so bad that you could create game-puzzle-breaking states with it, to where you were in certain levels without items that you needed to progress.