Board Thread:Love Live! School Idol Festival Lounge/@comment-24094680-20160626181951/@comment-24094680-20160626184324

That would explain the difficulty and the 900 combo, of course, but I don't think the stage will actually flip over, although I could be wrong.

As for that song, I think it must be a hack of some sort. Unless of course you can unlock that song in LLSIF. (Unlikely as it may be.)