Duke Nukem: Time to Kill

Duke Nukem takes on a third-person perspective in DUKE NUKEM: Time to Kill. Time-traveling aliens threaten Earth's future, and Duke must travel through time to ancient Rome, the Wild West, and a futuristic Space Age to stop them.
One there, he must run, jump, climb, swim, and shoot his way to finding the colored crystals that are the key to defeating the aliens. Before finding the crystals, use pipe bombs, gatling guns, and shotguns to put the bad guys out of commission. Luckily, you won't miss a second of the action because Duke becomes transparent when he would otherwise be obscuring the carnage. You also won't miss a single time-twisting alien by using the look function to aim your weapons. If blowing away the aliens is no fun, challenge your friends to a death match in the two-player mode. Can Duke save the world from the alien scum* DUKE NUKEM: Time to Kill contains the answer to that question.