Nearly every part of a Nintendo 64 has been painstakingly recreated entirely out of software to pull off such an amazing feat. It does this by dynamically translating the code that a Nintendo 64 uses into something your Mac understands. It was also last gaming console to use cartridge as primary storage.
It was even named Machine of the Year by Time. Nintendo 64 or N64 was the best gaming console when it was launched in 1996. It will run some games and some demos can be found on their website. It's much improved over the previous versions. Mupen64: This is 'Flea's port of Hacktarux's N64 emu. The demos it runs can be found at the Mac TrueReality homepage. Mac TrueReality: This N64 emulator availiable for Mac runs some commercial ROMs.