Eric, please take the time to update co-op or add something new to it, Co-op arena is broken at best, and really needs some work.
Pistole wielders often shoot off 3 or 4 rounds in succession, in a gun that only holds 2;
Shotgun Juggernauts punch and shoot at the same time, shoot backwards and even shoot through walls.
Shotguns in general are extremely overpowered, and have a ridiculous range; I spend more time running away from shotgun juggernauts then chokers
Gmal NPC's fire more rapidly than us humans possibly can,
RPG NPC's fire in the opposite direction they are aiming.
During gold rush, if the player carrying the idol leaves the game, the idol goes with them and never respawns,
If the party leader leaves the match midway through a round, the round re-starts. Normally, I don't mind as more kills = more XP but the game treats it as a round failure, so all stacked kickbacks get erased, and your gun goes back to the AK. Annoying when it's round 10 on crushing, and you had the PAK-80...
Despite these drawbacks, I still play co-op almost exclusively now, and have even joined a co-op clan. It would be really great if you guys could take a look at these bugs, or even add some new things like new maps, or even just better maps or possibly a team vs. team co-op tournament event where the winning team gets some cool character shirt or hat.
Please Eric, don't forget about us co-op people =)