Excellent.

Finally completed the first co-op campaign mission. Two of us finally managed to do it without dying and unlocked the achievement. It didn’t seem that hard when we finally did it, which was odd as it took us ages. The trick in the end was to split up, so we could come at the enemy from different angles. Very tense stuff. And very, very good stuff, even if some of the advanced features of the singleplayer game aren’t present.