I know the soundtrack isn't out yet, and I've always looked down on reviews that are written before a product is released. However, having played through Alan Wake more times than I can count (not really, 5 is hardly above my numeracy level :D) and also having listened to some of the tracks on the stripped down soundtrack that comes with the limited edition of the game (it's very good, but nowhere near as complete as this soundtrack), I feel justly able to comment on the quality of the music.
Some of the track titles may be story spoilers, so please be aware of that before you read on, as I will be mentioning a few tracks by name.
As the daft review title implies, Petri Alanko's compositions flit between quiet, subdued melancholy and sweeping majestic ecstacy. The former is at its best on tracks such as 'Tom the Diver' in which cello is used almost as a personification of tragedy itself, a stark and powerful emotional underscoring of certain story details that I will not go into here. As for the latter, the sweeping majesty of 'Welcome to Bright Falls' is a strong showcase of the beauty of Mr Alanko's music.
The two extremes combine more often than not, as evidenced by the hook of 'A Writer's Dream', a sweeping, rousing melody, as beautiful as it is foreboding and dark. I could mention every track that is either divinely beautiful or deeply sad, but there's no real point to doing so. They all fall within either description or a combination of both.
Well, not quite all. The tracks 'Hunters', 'Water Pressure', and 'Cross That River' do something a little different. These are the tracks that mark the soundtrack as that of a videogame in the traditional sense. By no means are they badly composed, far from it, but the addition of electronica and syncopated tribal drumming into the mix(while excellent during in-game action sequences) seems to jar slightly with the rest of the music on offer here. I could see the rest of this soundtrack working beautifully as an orchestral concert, an evening to just sit back and let the music take you where it will, but not those three tracks would really fit. That said, it is only my personal opinion that they jar, and others may not think so. They are still accomplished compositions in their own right, and some may love the change of pace that they provide.
In short, this is an astonishing soundtrack. Sure, some game soundtracks have a few standout tracks, but this manages so much more than that. The vast majority of this score is of such a high quality that it would be an almost criminal shame were it to be overlooked. This deserves its place in your soundtrack collection, nestled somewhere in between 'The Lord of the Rings' and 'The Godfather'. It really is that good. But I will add one final point. If you buy this soundtrack, I recommend that you buy the game too. The music works on its own, but in combination with the story of the game, there is a certain level of subtext that really expands the music's scope and depth. Plus, if this is the quality of the music, you know that you're in for a treat if that same quality is evident in the rest of the game. It is.
Even if you don't pick up the game, this soundtrack really is one not to miss.
In a word: breathtaking.
In two words: buy it :D