The game was released for PC last Thursday, with the Xbox 360 version's DLC included, and it quickly shot to the top of the Steam charts.
In a post on the game's official forums, Remedy EVP Aki Järvilehto writes: "We are very happy with the sales, and hitting number one on Steam at launch was nothing short of amazing.
"We recouped our development and marketing expenses during the first 48 hours. And yes, we're certainly very excited about PC."
A standalone adventure, Alan Wake's American Nightmare, will be released for Xbox Live Arcade this Wednesday, February 22.
Read about the making of Alan Wake here.