Remedy announced via Twitter that help is on the way for those of you stumbling through a living nightmare of inaccessible post-game content. "If you've redeemed your code prior to release Microsoft will be sending out new codes to you via your email on XBL," the developer said. We're checking with Microsoft to find out exactly when those emails will go out.
In the meantime, catch a new trailer for the DLC after the break. Or don't, if you have yet to finish Alan Wake and fear spoilers.
Update: The codes are starting to be emailed out. Make absolutely certain you have a working email address tied to your Xbox Live account, or it's back to "living nightmare" time.