That's intersting that Mega Drive had a Master System converter, and, imo, at that time, it runned perfectly.
Of course, it was a hardware piece, not a software, and I have no idea of how it worked. But, isn't intersting that, with commercial interests behind it, it becomes easy to develop emulators?
That's why I admire the coders who spend all their free time making such amazing things in so limited consoles.