Why do alleged cheat codes for classic games frequently not work? [closed]

Question

Example: https://gamefaqs.gamespot.com/nes/563470-tetris/cheats

Warp 10 levels ahead[:] Select the level you want to go to and hold A, then press START

If I select the level and hold/press A, the game starts immediately. A is an alias for START on that screen. I've tried numerous times to hold A and press START, and many other variations of that. Nothing works. It always starts the game at level 9 (the selected level).

I'm trying it on the original game on an original Game Boy.

This is not the first time I read about some cheat code which appears to be just made up. They just don't work.

If it's the case that they only work on "certain versions" of a game, such as on PAL but not NTSC, what could possibly explain that? Why would they have such differences to the "game logic", unrelated to displaying the game properly for each region?

What's with all those fake cheat codes/"tricks"/Easter eggs?

Answer 1

As you've said you're playing the Game Boy version of Tetris, but you are attempting to use a cheat code from the NES version which is a completely different game.

As with many games from that era the versions for different consoles would often be completely different, not merely ports of the same code. The NES version would have been written by hand in 6502 assembly code while the Game Boy version would have been hand written in the Game Boy's Z80ish assembly code and designed for the smaller screen resolution which supported fewer rows (so they played differently which is why some people prefer the Game Boy release despite it being graphically inferior compared to the color NES version).

As far as Japan/US/Europe games on the same console there used to be much larger regional release windows. Gamers in the US who had just started playing Super Mario Bros 2 were hearing news from Japanese gamers who were already playing Super Mario Bros 3. Because of this there were often larger differences between releases - not just translations but also adjustments to difficulty, new or removed enemies and different cheat codes (since the original purpose of cheat codes was to help Q&A testers working on a specific release of the game).