*is now brain dead*
So I've just spent hooooooooooooooours playing this thing, and I came across a few bugs.
1) The not-really-a-big-deal-thing - Once your collecting level hits the max and gems are drawn towards you, sometimes they just kind of end up orbiting you. I chased one of them around the screen for several second before finally having to throw myself off a cliff to catch it.
2) Whilst fighting Nightmare, when he summons the giant bolders, after one wave of them there were dents left in the florr and they stayed there throughout the rest of the fight rather than disappearing like they're meant to. Again only a minor aesthetic thing but just mentioning it in case it means something underlying is going wrong in the script.
3) There appears to be a problem as the final gem IS NOT there :P Seriously, I got stuck at 99.7% just running round and round trying to find that damned thing day after day. I shall await the video walkthrough so I can finally find it and rest easy.
Sorry for the mammoth review, but it's a mammoth achievement so I felt it worth the time it took to actually think about it. I sat and tried to come up with any possible tweaks you could make to it, but couldn't think of any. So I'll just give you three thumbs up and tell you to go work on the sequel.
Now if you don't mind, I'm off to lie down before I fall down ;)