It was in fact so inaccurate that many ROMs had to be modified to run under Nesticle. There's actually a tag in the goodtools filenames that indicates a ROM has

It was in fact so inaccurate that many ROMs had to be modified to run under Nesticle. There's actually a tag in the goodtools filenames that indicates a ROM has been modified to run under specific emulators (I think it's [f], but I don't remember 100%, and I'm not going to look this kind of stuff up at work). Later emulators that made use of game-specific hacks (e.g. ZSNES) would store the hacks in the emulator instead of the ROM, patching the hacks into memory at load time, so people could use the same accurate ROM dumps in both accurate and inaccurate emulators.