I recently noticed that there is an issue when you roll a blue gem/boulder/thing by anything other than a green tile-> it replaces it with a green tile making the stairs unusable on the way back up. I'm sorry you couldn't finish it :(
Oh haha I thought that was a feature. i.e. the stone rolling by damaging the stairs so they're unusable. There was a different way to solve that one, in any case.
