To answer your question, Chupperson, you can play the originals, and the Marioized new versions which are better.
Anyhoo, I've unlocked the other 6 games, Fire Attack is awsome, and I've got a whole bunch of things in the Gallery, like Game and Watch History. It shows every game released on the Game&Watch, and the exact dates. I have taken all the Mario-related ones down, including Donkey Kong Circus and Donkey Kong Hockey!! (!?) And, I've gone through three sets of batteries just this weekend from overplaying!