Wow, this is a great level pack (so far, I'm stuck on A Fearful Symmetry; I just don't know what I'm missing). My favourite level has got to be Lemmings in Motion. I don't think I've backrouted anything, but the level 'Clues' is a little uninteresting, and 'Roundabout' felt a little too difficult for it's rating. Other than that, it's been really fun to play.