When you push Start, you're greeted with this screen. The "Progressive" mode is not selectable in this beta. I think it's safe to assume that the Progressive mode will likely be Marathons with scripted modifiers and all that. Also note the "INSERT CARD" at the bottom-left of the screen. In this beta there's no USB support, but it will be in the final. Presumably it'll save song records and modifier preferences, but who knows what else.