The newest version of the Unreal Engine (obviously. ). You may remember Unreal Engine 3 as the engine that ran such games as Mass Effect, Gears of War, Batman Arkham Asylum/City, Borderlands 1&2, Dishonored, the recent Mortal Kombat reboot, Silent Hill: Downpour, The Last Remnant (just kidding. No one remembers that one), XCOM Enemy Unknown, and god knows how many more. This console generation pretty much ran on that one engine.