At E3, Irrational Games showed a fifteen minute gameplay demo of BioShock Infinite to the press. Today they released this footage to the public.

BioShock Infinite takes place on Columbia, a giant floating city created by the American government. The city was meant to be a tribute to American exceptionalism but the grand vision for the city was spoiled by in-fighting. A bloody civil war broke out in Columbia between the Founders, the city's ruling class, and the violent resistance group known as the Vox Populi.

In the middle of this war-torn city is Booker DeWitt, the player character. He's an ex-Pinkerton agent tasked with rescuing Elizabeth, a woman with mysterious powers. She's able to manipulate rifts in the time-space continuum - a power explained more comprehensively in this developer diary. Both factions of Columbia, as well as a giant mechanical monster known as the Songbird, are searching for Elizabeth as well so Booker will have his work cut out for him.

The footage is a good cross-section of the game. The slower exploration and dialogue segments eventually give way to a massive gunfight between Booker, the Vox Populi, and their massive war-blimp. You'll also get a good look at the Skyline, Elizabeth's reality-bending abilities, and a certain George Lucas film.

Infinite will arrive in 2012 on the PS3, Xbox 360 and PC.