Relic's late addition to Warhammer 40K: Space Marine, the standalone "Exterminatus" co-op mode, arrives today. As promised, the add-on comes free to Space Marine owners.
As of now, we can only confirm the new mode's availability on Steam, though it should also be released for PSN users as well, according to THQ. Xbox LIVE has yet to receive the DLC but should some time today. Either way, you can expect an update that adds Exterminatus to the menu and serves as a guide through the content download process.
At launch, Exterminatus comes with two scenarios -- "Assault on Hab Center Andreas" and "Escape from Kalkys Facility" -- with global leaderboards, score modifiers, and the same three classes available in multiplayer.