Thought I'd toss up my quick review. I spent about two hours last night in co op. We played the main coop mode, campaign, at the hardest difficulty level, "sniper elite". This difficulty ramps up enemy assn and damage, gives you"realistic"bullet drop and wind effect, removes options that allow you to tag enemies, and more.
We had a really enjoyable time playing. Graphics are good (not great, this isn't bf3 it cod), but there are good draw distances, nice particle effects, and little additions like heat ripples and the like. They do a goods job with level design.
AI is the thing I kept reading about in reviews that dropped this game in ratings. AI is as bad as any game. Sometimes they charge forward, but they always try to take cover. We've been flanked, and we had others cower behind a truck, but nothing that made us enjoy the game any less. Do far so good, its not a run and gun game, on the sniper difficulty level you never really want to go toe to toe.
Hope this helps anyone on the fence of buying this game!