Re: version differences?

The reason this question came up for me is that one of the emulators i use had no cheat codes for the games i have so i had to get an older version of the game.

There's no website that tracks and describes every single version difference out there, but The Cutting Room Floor Wiki (tcrf.net) has a lot of good information on that front. The version numbers just come from the games themselves, and back in those days developers were unlikely to even tell consumers that a new version of the game came out, let alone offer patch notes. As for cheat codes, that depends on how much they changed between versions. Those kinds of cheat codes work by altering memory at certain addresses, and if the memory layout changes between versions, then it might break the cheat code. However, when that's the case the cheat code author will usually provide different versions of the cheat code depending on the version of the game.