Painkiller Battle out of Hell Trailer

PainKiller is a first-person shooter video game that has 24 levels of seemingly unconnected designs that include medieval castles, factories and lunatic asylums.

Five of the levels are "boss levels" with some of the largest FPS bosses to date. The game takes place in Purgatory and Hell. It is notable for using the Havok 2.0 physics engine extensively.