I'm right back where I was on my original file on HoD; 86.6% of the map, and no clue what to do next. I keep running around the castle, but always end up at either a wall blocking a door, or a locked door.

And dammit, I think there is an upside down castle.

If Tweeter can't tell me where the thing that lets me fly or super-jump or something is, I'm gonna have to go to a walkthrough.