Gotham City Impostors is a team based first person shooter. There are two sides, one side is dressed up like Batmen while the other is dressed like Jokers. This looks like a hilarious game filled with quirky characters and crazy weapons. I guess you could compare this game to Team Fortress 2 but know this, Gotham City Impostors is not a class based shooter.
This game is being developed by Monolith, the guys who brought you the Condemned and F.E.A.R. series. Gotham City Impostors is going to be a downloadable game for XBLA, PSN, and PC and is set to be released in 2012.