Maybe you could add a system that keeps track of which combos you've already found (as in, an updating quest listing Fire + Stone = ? , Human + Fire = ?, etc.) ? I mean, obviously pen and paper does the job, but it gets confusing very fast. Also maybe some different music for the cutscene endings.
The game froze during one ending, once the peon was on the second island he just stopped moving (this after I'd already gone through that ending on the same playthrough).