What I find interesting in addition to that is how much slack most software allows. I remember lurking on the alt groups when emus were being discussed for things like an amiga or pc. They were talking sub cycle accuracy would be totally necessary for anything to work at all. Yet most software seems pretty chill with 'sort of close' results. It is oddly counter intuitive. Intuitively they were right but ended up being wrong (mostly). Some bits though you need that accuracy. Mostly you dont.

I think a lot of software companies would do like what you did. Where they would check for some sort of thing that should be there, or not, or too much of something. But the emulator would or would not have it. I think in many cases it would be things like checking to see if 512k of memory was available, when the real box would have 128k. That was usually for things like copiers I think?