Just received a message from Xbox: "Thanks for being an Xbox One early adopter. To celebrate Year One, we’re giving you LIMBO when it's released. Stay tuned, your free code will arrive here."
Awesome.
http://www.reddit.com/r/xboxone/comments/2n2kot/message_from_xbox_giving_me_limbo_when_its/
I got this message, too, by the way Pretty cool!