Although it was around the web for some time,
There was nothing but rumors.
untill now, quote: “Whether it’s a complete walkthrough to the gritty Cold War-era Campaign mode, tips and tricks to rank up in Multiplayer, how to excel in Co-Op, or fight back the relentless Nazi Zombiehorde…”"
this was written by the developpers!
This was also posted on the website of Best Buy for a short period, but got removed.
you might remember them from Cod 5: World at war!