Final Fantasy VII - A secret FFIX boss (New Threat mod)

A fight against an FFIX cameo boss. This guy hits like a truck: his Flare Star, Doomsday and Meteor attacks can almost OHKO a Wall'd party at full HP, you need to be on certain levels to avoid Level X attacks, he doesn't take much damage, and he keeps healing himself. Just like in FFIX, his weakness is having a relatively low amount of HP, so better take him down fast, before he takes you down. The FFIX boss music arrangement is probably the most epic version of the song I've heard so far.

About playing the piano: you need to play the Highwind theme, but it's harder this time, as some of the piano keys are "broken" and play a distortion effect for extra challenge, rather than playing the correct note.