~FREE TO PLAY~
So far I think is a great game (superior to tf2), we can organize events for those that are part of the GTAF Group.
Some details copy-paste from wiki:
Gotham City Impostors is a first-person shooter multiplayer-only video game set in the universe of DC Comics' Batman. Developed by Monolith Productions and published by Warner Bros. Interactive Entertainment, the downloadable game is played from the perspective of two teams each trying to kill the other: one with people dressed like Batman and the other with people dressed like his archenemy, The Joker. It was released on Xbox 360 via Xbox Live Arcade, PlayStation 3 via the PlayStation Network and Microsoft Windows via Games for Windows – Live in February 2012. The game was re-released on Microsoft Windows as a Free-to-Play title in August via Steam using Steamworks. The game is a six versus six first person shooter multiplayer game featuring customizable characters. Players take on the role of either amateur vigilantes (the Bats) or villains (the Jokerz). The game features a range of both traditional and imagined weapons.