Again I haven't played the mod but from what I gather it's mainly about shooting things and trying to stay alive. From the gameplay vids it looks like there is a fair bit of cooperation involved but I wouldn't expect incredably complex tactics or stratergy, more like cover all the sides, move wounded to the back and let them heal ect. I'll let you know on monday after I get my hands on it. Seems like survival was a big part of the mod though, you had limited ammo and healing ect.
http://www.youtube.com/watch?v=DwwPJ-KiN7c...feature=related