In this case, it's mimicking whatever gaming system you choose. In order to play any of a particular system's games or ROMs (read-only memory files), you must first download an emulator that will allow your device to mimic the original device's attributes.
Depending on what system you're using, a Mac, Windows PC, Android device, or BlackBerry, each emulator will run differently or not at all (most sites list what devices are compatible with each emulator). There is an emulator available for almost any gaming system you can think of, from Super Nintendo to the PS2. Is it truly impossible to do? How It Works You can find a few tutorials and videos out there on getting Game Boy Color or NES games on an Android device, but the most elusive mobile emulator is for Game Boy Advanced (GBA) on a BlackBerry.
