"Right from the outset we realized that this was going to be a monumental undertaking on the tech side," Irrational tech director Chris Kline wrote on the dev's forums, "but decided it was a challenge that we simply had to take on in order to give gamers the kind of quality experience they've come to expect from Irrational Games and BioShock." Kline reveals that the team considered using the heavily modified Unreal Engine 2.5 they'd already invested in, but it was "too under-powered and unwieldy for the depth and complexity of the gameplay and narrative we had planned." So Irrational stepped up to Unreal Engine 3 and began modifying its base.
Most notably, Kline writes that he and his team needed to do some serious work on account of Infinite's unique setting: the floating city of Columbia. "The very ground beneath your feet could fall out of the sky at any moment, which makes for some awesome gameplay and visuals but required us to create a completely new technology that we're calling 'Floating Worlds.'" (This type of gameplay is evident in the trailer below.)
Also under construction is a new lighting system, which DigitalFoundry calls "state-of-the-art" and "ambitious to say the least"; a jobs-based processing architecture to take advantage of our multicore game consoles and PCs; an overhauled AI system "concentrating on smooth, realistic animation"; and a new audio pipeline that features "a custom sound propagation system (so voices properly echo down corridors and around buildings) and a dynamic wind audio system that reinforces the dynamic weather in the world."
If this all sounds pretty incredible (and we're inclined to agree!), we want to remind you of the game's 2012 release date. Who knows, in 2012 this stuff could be on our iPhones ... or maybe we won't even have iPhones anymore.