From 3D Realms:
The third chapter in the Duke Nukem series, and the first with a 3D perspective, Duke Nukem 3D is set sometime in the early 21st century, in a ravaged L.A. that was overtaken by aliens while you, as Duke, were being abducted during Duke Nukem II. Duke, upon returning to Earth, finds himself with another mess to clean up and another alien race to exterminate. Duke is a can-do hero who realizes that sometimes innocent people have to die in the quest to save Earth, so gunfire accuracy is not a real concern to him. This game includes a long list of cool features that haven't been attempted in 3D action games before, including a mine that sends out a laser trip beam and can be placed on any wall--perfect for multiplayer games. There's also a shrinker ray that reduces an opponent to the size of a G.I. Joe, at which point they become foot fodder. You can swim underwater and shoot players who are outside the water or vice versa.