Yeah, the game that plays is dependent on the start buttons used. However, the reunion machines don't have a unified front-end, either. They just switch between games on the fly whenever you choose the appropriate start button. If you walk up to the machine and it's showing Ms Pac Man, you can dump in a quarter, hit Galaga's start button, and it'll fire up a game of Galaga. Then, when the game is over, it'll just sit there in Galaga's attract mode until you dump in a wuarter and hit a Ms Pac Man start button. MAME and MAME frontends don't work that way. You typically have to enter a game, insert credits, play the game, and then back out when you're done if you want to play another game. The same set of start buttons is always used.