Destructible environments are a great touch and add to the sense of chaos during large firefights, and nothing says wow like a huge mechanical spider exploding after a few seconds of melting it with your satellite laser.
It also takes a way - out premise - this time two agents trying to foil the nefarious schemes of a mad scientist shortly after the American Civil War to conquer the United States with a huge mechanical spider - and pursue it doggedly to its end.