Update: The trading system does not actually involve ripping off faces of any sort. The Behemoth has clarified that rather there is a trading post in-game where players can view their other players’ inventories and select what they want and the other player can do the same.
The Behemoth, developers behind XBLA sensation Castle Crashers and upcoming title Battleblock Theater, were kind of enough to meet with me at San Diego Comic Con. During that fantastic interview with Dan Paladin he revealed and explained Battleblock Theater’s unlock and trading system. (Link to interview forthcoming)
Fans and players of Castle Crashers will recall the massive frogelope (antler laden frog, I don’t know) wherein all the weaponry was stored was sometimes more trophy case than armory as players without the unlocked weapons could not access them. To circumvent that players would take the weapons into levels, swap them for easy to find weapons and allow newer players to pickup the rarer weapons they didn’t have. Dan says Behemoth got get rid of all that convolution and put in a full-fledged trading system into Battleblock Theater.