Duke Nukem: Zero Hour. Surprisingly, it's a very good game. Aliens go through time to try to screw up history. Whether it's in the futuristic holocaust with cannibals, in the wild west with western style aliens, in Victorian England with zombies, or back in the present, with Duke clones that are out to get ya. Personally, I like it and I think it deserves to go on VC.
The wild west, alot of shooting is a given...
The statue of liberty falls to the Futuristic Holocaust era
Nukem's Nuking zombies in the Victorian England era