The Gameboy and Gameboy Color thing has always gotten me thinking as well. For instance, the original Gameboy did NOT sell over 100 million units but for some reason, it's officially listed as such because everyone lumps the Pocket and Color Gameboy into the same line. It doesn't make any sense.
I would say that if a game was backwards compatible with the original Gameboy, then it wasn't exclusive to anything but Nintendo. It was a "Nintendo" exclusive.