The latest trailer for upcoming co-op shooter from Visceral Games, Army of Two: The Devil's Cartel, demonstrates the Overkill mechanic.
Army of Two's gun wielding protagonists Alpha and Bravo shoot their way through a map, filling up the Overkill gauge as they do. Once the gauge is full, Overkill kicks in for a period of time, where the player becomes invincible and weapons have the ability to blow up buildings and other structures.
Army of Two: The Devil's Cartel is set for a March 26 release on Xbox 360 and PlayStation 3.