I remember when the CPS II emulation was relatively new, somebody somewhere made an elaborate hack of X-Men CotA using the cheat system in an emulator. I think it was Nebula, but Final Burn is also a possibility. The cheat, when activated, completely changed the game mechanics and made it play much closer to the VS games that would follow.
There was a web page that listed all the changes to the game engine and had links to download the cheat file to play with. Unfortunately, I can't find the site now and Googling for various combinations of "X-Men arcade emulator cheat hack" hasn't been giving me what I'm looking for.
Anybody remember the link or have the files?