[Update: Konami has informed fans via Twitter that the problem is resolved, but some people are still reporting issues. Contact Konami with your concerns if you are still encountering errors. I can confirm that my code finally works after the notification.]
Many users across the net (myself included) are reporting issues with their codes, and some have gone as far as to reach out to Konami and Microsoft to find out what the deal is.
Right now, Microsoft has confirmed that these codes are valid, they just haven't "activated" the system yet, and to wait 24-48 hours from today to try again. So basically, just sit tight, as they are working on it.
For the record, I was able to redeem my Gray Fox code on the PS3 instantly.
Get more destructoid: We're indie-run, blogging for the love of it, and our site will always be free. Optionally, you can support us and get: (1) Faster pages from our cloud server (3) Wide(r)screen (3) No big ads on Dtoid, Japanator, Tomopop, or Flixist (4) Auto contest entries, and (5) Dibs on betas & downloads. Try it out
Unsavory comments? Please report harassment, spam, and hate speech to our moderators, and flag the user (we will ban users dishing bad karma). Can't see comments? Apps like Avast or browser extensions can cause it. You can fix it by adding *.disqus.com to your whitelists.
destructoid's previous coverage: Metal Gear Rising: Revengeance