I've put down 3 hours so far, playing in normal difficulty.
The overall presentation, visuals, and "feel" of the game is amazing. The Stray Sheep segments are really really fun! I'm really liking the story and cutscenes so far.
The block puzzles are a bit more fun than I had expected actually (I didn't try the demo). There are some minor annoyances. Controls are sometimes weird (I never know how to go left or right while hanging on blocks), and evading trap blocks seems a bit random sometimes. Nevertheless, I really feel like they succeeded in creating nice nightmarish segments of gameplay that fit very well.
I also really like the questions you get asked and the little online feature which tells you what other players answered. It does seem evident though that many players are basing their answers on the ending they want to get, and aren't being honest. Some results are really surprising! (It might just be me who wrongly expected some answers though!)
Unfortunately, the sound in the game is really, really off. And I'm not only talking about the obvious sound volume problems. The voices seem to have been compressed quite heavily. The s'es in particular got completely crunched. The game is on a freakin' blu-ray, there's no reason we'd have to get such poorly recorded/processed voice acting in a 2011 HD game.
At least the music is pretty good!