Duke It Out In DC is a great addon for Duke 3D that has amazing level design and atmosphere, and has more Duke action.

User Rating: 10 | Duke It Out in D.C. PC
Duke It Out In DC is an addon for the classic Duke 3D, and takes place in Washington DC. Duke is sent there in a helicopter to fight against the aliens that have taken over the city. Duke Nukem's classic character and attitude is used well in Duke It Out In DC. The addon doesn't have any new weapons, but it uses the existing ones very well. It does have lots of cool new artwork, though. The game starts out at the white house, and as you move through the levels, you'll visit the Lincoln Memorial, the capitol building, the smithsonian, and many other places in DC. The levels were designed by Charlie Weiderhold(who worked on DNF from 1997-2006), and they are all very well designed. There's even one level named Dread October where Duke moves through a very detailed submarine underwater and launches a missile from inside! The game has a total of 11 new levels, including one secret level(Which is AWESOME). Overall, this game is a classic and all Duke fans need to play it!