THQ has confirmed that Warhammer 40,000: Space Marine is getting a co-op mode. The feature will be patched into the game thirty days after launch, and will be a free addition. It's been mentioned that it will only be free to "brand new" copies, implying that the online pass system will lock used copies out of the update.
The publisher has said that details are coming this month, but GameStop says that co-op will support five players, which is an odd number indeed. Should be interesting to see how Relic's implemented this.
It seems like a very strange announcement. Was this feature deliberately held back to ransom it to used gamers, or has it been shoehorned in at the last minute? No way of knowing for sure, but it's quite an unorthodox maneuver.