You've been doing a great job killing those Batman and/or Joker imitators in Gotham City Impostors and Monolith wants to reward your hard work with some free DLC. Available starting today on Xbox 360, this content update adds a new level called The 25th Floor, a rooftop arena with a lovely view of the Gotham skyline.
In addition to the map, there are also some new outfits and a few new weapons: a semi-automatic pistol and a katana. Finally, a new toxic gas support item is available, which should help you injure and disorient your opponents with stinky, stinky gases.
PS3 and PC players will have to wait for the DLC, though Monolith and WB haven't revealed exactly when this content will come to those platforms.