As someone who has just gotten into this hobby, I'm so glad you asked this. I've been trying to figure out how to display the controls for the various games, and while I can hit pause in MAME to bring up the list (button 1, etc.) it would be much better IMO to have a graphic for each game where you could include combos (for fighting games) or a diagram for guests (so they know, for example, what button 1 is on the control panel).