As noted on the Gotham City Impostors Website, today is the worldwide release date for the Windows PC edition of this offbeat Batman-based, multiplayer first-person shooter. The game is also available today on the PlayStation Network in the Americas, and it will be released tomorrow for PSN in other territories and for Xbox 360 worldwide. Digital distributors offering the download-only Windows edition include: Best Buy, GameFly, Green Man Gaming, Impulse Driven, and Steam, and there is DLC on Xbox.com. Here's a bit on the game:

Gotham City has gone insane! Batman is up to his pointy ears in unwanted "helpers" determined to dish out their own bloodthirsty brand of vigilante justice in his name (and image). Meanwhile, a small army of self-appointed junior Jokerz has turned the streets of Gotham into a barmy battlefield of bullets, bodies, and bear traps.