A beautiful huge world, which you are not allowed to explore.
However when I finally got my hands on the game, I was so disappointed, since I found the world is simply a dead backdrop, and you have no ability to actually explore or interact with it. There's always a fence, a rock, a building or something blocking you for going anywhere else than in the one direction the game designers command. I imagined you could lose yourself in this big, black forest, with monsters chasing you around. But no...
Alan Wake goes like this: Go from A to B, trigger scary cutscene, fight x monsters to continue, go from B to C, trigger scary cutscene, fight y monsters to continue and so on. You are left with virtually no choices as the story progresses.
And after a while the scary cutscenes become predictable and feels more like a distraction than something adding value. I want to play the game, not watch it play itself...
The great graphics helps, and it is indeed quite atmospheric sometimes, but I still cannot get over the initial disappointment. Perhaps I have just been playing Skyrim too much lately, it's hard to see all that freedom I've been used to just disappear.
Personally I think watching the game on youtube is enough, since the lack of freedom and choices makes it into more of a movie experience with game cut scenes than a game with movie cut scenes.
Don't let this disencourage you though, since a lot of people do not mind this kind of linear, story driven gameplay. And if you don't then Alan Wake is one of the better implementations out there.