Something I have always wondered about why the ROMs change with each release....

[Pipercub]

With every other emulator I have used, Atari, NES, etc. the ROMs are unchanged between versions. Since the ROMs are the raw dumps of the game program itself, why is it that they are changed with each release? What changes are actually made to the ROMs? How is gameplay or appearance altered?

[SirPoonga]

As noted in many other threads, changes are usually name changes.  Some changes are because they found out the dump is a clone, not the actual game.  There are many reasons for a change.

With consoles you don't have this problem because the game has to go through a certification process in order to be an official game of the system.  Note how all NES carts, n64 carts, Gamecube discs have the official Nintendo seal on them.

[vitaflo]

You will also notice for console systems for every good dump of a game, there are 20 "bad dump" and "overdump" versions of the same game.  Quite annoying.

In MAME, if a bad dump, overdump or incomplete dump is found, it is redumped and the rom is updated.  Otherwise you would have 20 versions of bad dumps for each mame game as well, which, thankfully, we don't have.