This game is a perfect blend of entertaining puzzles, and superbly-written novel.
Instead of detailing the game's pros and cons, I'll talk a little bit about my experience playing it. There's not much to tell, actually; I simply didn't come out of my room for an entire weekend. The story reads as though Michael Crichton were responsible for the movie Saw, laced with an extra dash of mind****ing for good measure, and I found it compelling enough to purposely deprive myself of sleep -- by setting my alarm -- just so I could wake up early and play the game some more after being up half the night already.
This game's story made me think. Not because it was a necessity per se, but because I couldn't help it. Anybody who likes to read books, or who likes to do puzzles, should have bought this game yesterday. If you like intriguing and creepy versions of both, in game form, simultaneously, then you'll probably wind up being as bat**** enthusiastic as yours truly.
My highest recommendation.