A steampunk shooter game set during the Civil War era, if I'm not mistaken. It evidently has a bad rap from people saying it's a clone of games like Assassin's Creed (which I haven't played), but even so, this is a wicked game, and a bit hard, too. The only thing I don't like is that you can't invert the horizontal camera controls.

I've never played any Steampunk, would be interested to find some.