As there is only one person that I usually play Co-Op mode with, I've mostly been doing it two-man. It's definitely challenging (the final area on The Sanctuary, for example, is pretty tough even on Normal if you don't cheese it by staying in the spawn area waiting for dead teammates to revive), but we did Nepal Warzone on Hard in one night, and it was a hell of a lot of fun. So we decided to try it on Crushing last night.
And damn, it's BRUTAL. Took probably 2 or 3 tries (as in after having failed the mission) to get the strategy for the second area down, and then the 3rd just owned us. The only good cover area is behind the desk near the alleyway, and with the enemies who drop down from the windows in the alleyway being semi-random, we often aren't able to tell when an armored shotgun enemy drop down from there. And if it happens while we're running between cover due to a grenade, there's almost no chance to react fast enough to deal with him first.
That said, I loved every moment of it (even the moments of cursing after I got shot-stunned while running from a grenade and then got blown up by a second grenade). And if anyone else is interested in doing Co-Op/Survival games (we usually do them pretty late at night, like after 2AM EST, as I'm a night owl and he's on PST) and have a mic, lemme know or just send me a PSN friend request (name is GokieKS)
