In short, the level design. I felt the hints of what annoyed me when I was playing the two Galaxy games, and this video really summed up what I find terribly wrong (as opposed to brilliant) with the design: https://www.youtube.com/watch?v=dBmIkEvEBtA It's lazy design. There are other complaints (even other specific issues with the level design I experienced) but that's the big one, it's so bad I don't want to play it ever again, let alone finish it.