...will include a new Exterminatus mode called Chaos Unleashed. In this update to the popular co-op mode players will take on the role of Chaos Space Marine as they take the fight to both the Ork horde and Imperial Guard forces. With brand new boss rounds, new co-op arenas and new enemy units like the Imperial Sanctioned Psyker this mode is a must-have for players looking for a new challenge.
As well as the Chaos Unleashed Mode, the Space Marine add-on pack also includes three new multiplayer maps Habs Ablaze, Station Tertius and Aquila Canyon which can be played in all multiplayer game modes. The pack will also include ten new achievements and trophies.
As someone who hasn't gotten Space Marine yet this news is nothing but salt on an open wound. I plan on getting, and I may be closer to getting it than I thought, but until then this news burns.
You can read the whole announcement at the Space Marine site.