MacMAME achieves this by running the original program code found in the arcade games. As such, it is much more than a reproduction, it is essentially that same game running via an emulated layer inside your Macintosh.
Many people ask what MacMAME is and how it works.
Put simply, it's an emulator whose sole purpose is to emulate the inner workings of arcade game machines. It does this by fooling the original program code, contained in ROM chips, into thinking they are running inside the real machine when in reality they are running on your Mac. MAME, which stands for Multi-Arcade Machine Emulator, is the product of a group of people who have teamed up to emulate as many of these games as possible. It is an open project with full source code available. This is done in hopes that years down the road, whatever computer you have, you will still be able to find or create a copy of MAME to run on it so that these classic games live on forever.