I just completed URU and I have to say I am disappointed. Not many puzzles where logical and a lot of the time I would end up looking through a walkthrough for the obscurest of answers. See, with a lot of puzzle-games when I reach for the walkthrough, I will then go say "I see" and move on, but with URU it's more of a "How the hell is anybody supposed to figure that out!"
One of my books still hasn't arrived from Amazon. Not sure if I should send an email or not. Probably give it another week just to be sure.