Found all the endings except the one where you collect all the gems and one other ending.
I currently can't even imagine how to get all the gems in one playthrough...
Edit: I found the last mentioned one. Man, that one was so obvious that I completely overlooked it... :-D
Well, onwards to the gem one which is probably the hardest cause I have to think hard which items to get or not to get :-/
EDit edit: by the way, I'm playing the 8 endings version, not the 6 endings one :-)