MichiGen: I think GOG was trying to include the soundtrack. But it's not possible because buying the Collector's Edition on STEAM would lost all the sense.
Alan Wake cost 28€ on STEAM and 30$ on GOG. If you want the ingame developer commentary, Alan Wake Files book in PDF and soundtrack you have to pay another 10€ on STEAM for this stuff. But on GOG you already have the ingame developer commentary, PDF book and moreover making of videos, writer in the cabin videos and night springs episodes (from which 2 or 3 are exclusive only for GOG version).
So adding soundtrack to GOG version would make it superior and much cheaper than the STEAM version. And calling a STEAM version Collector's Edition after that would lost all the sense. Let's leave them the soundtrack and be happy with all the bonuses which are in the GOG version for a very good price. I personally bought the retail CE which contains the soundtrack and also the GOG version because it's DRM Free. :)
Thanks for replying, you almost sounded like a GOG representative (A compliment).
And yes, I understand the reason behind not releasing the soundtrack, but again GOG has many deals better than STEAM. Take Unreal Tournament 2004 for example: It costs $14.99 on STEAM and $9.99 here.
Anyways, It would be great if a soundtrack is possible since the music is awesome. If not, I can understand why.