In an attempt at getting some recreation in, I've played some Team Fortress 2 in the past week or so, which I haven't done in several months. I took the opportunity to try the new "Mann vs. Machine" format, which pits players cooperatively against a bunch of bots. Being the fan of cooperative play that I am, I figured that I'd give it a shot.
That said, there wasn't much of anywhere to go for TF2 as far as cooperation is concerned. Being a team game (hence the name), it's already fairly cooperative. While the opponents weren't manned by humans, there were a lot of them, and they seemed to have more hit points - especially the gigantic ones that can apparently come along. Also, weirdly, there seems to be a limit of 6 players on the defending (read: human) team.
There's also an upgrade system, whereby one's weapons - and even one's class itself - can be temporarily upgraded with money found around the map. It's entirely necessary to survive the tougher waves, which at least removes repetitiveness from a long map.
There is one thing that's just really odd, though: There's no full health/ammo cabinet in spawn.