Stuck on 16, and then I started trying really crazy stuff out of desperation and managed to get myself trapped - I bound 2 areas together and then dropped too low to be able to undo them. So it at least needs a reset button for cases like that.
Got stuck in chapter...4? I think. I died, and got respawned between two doors. The eagle can't fly out of the area either. And with no way to kill myself, I can't hope to respawn again and hope that one of the doors isn't there next time. = P