Straight up awesome game. Not too hard, but not easy either for sure! Specially if you want to earn all medals. Just nothing else but good things to say about it.
And for anyone who has problems getting the last medal, there's a scrap piece of crystal hidden. It's easy to find it and makes more sense if you think about it. You blow up the entire ship to the point where nothing of its inside remains, yet still there still is a piece of crystal. Think about it, space man.