After examining my map for a while, it looks like it's possible to get stuck if you collect the bottom-left crystal while upside-down. Is that what happened to you?
It's not a method I had considered for getting there, but at least it's easy enough for me to add a way out without breaking anything else.
I got stuck there, too (the crystal in the little square box with one opening), though I think I had gravity pointing to the right, such that I could fall through the opening, but not jump back out.
But man is this game neat. Nice job figuring out all kinds of things to do with a game element most just think of as a necessary evil: the edge of the screen.
