Has there ever been an attempt at emulating the Advantage joystick? If not, I think that'd be kind of a cool implementation, as you can actually control your rate of fire on the buttons. I'm not sure if this could be something you could adjust on the fly via emu though. Also, it was a crappy effect, but the slow-mo feature of repeatedly hitting Start could be implemented, along with the 1/2 player switch. Just an idea.