I am happy to report that this is an awesome version of an awesome game. Duke Nukem 3D didn't really impress on a technical standpoint when it came out, but it was great for other reasons. It had great level design, a wide selection of unique (and typical) weapons to fight your enemies with, and a memorable, funny, protagonist to top everything off. Something FPS games didn't really have at the time and still don't really have today.
Thankfully the game on its own (even the original DOS version) has aged like fine wine. The shooting mechanics are still great. The levels, while rather maze like at times, are still clever and fun to traverse, and overall the game is still a ton of fun.
This version is simply outstanding though. The few things that have aged poorly like the poor mouse control, and the limited resolution options are fixed here. The controls are fantastic, and you can run the game at high resolutions.
Of course the high resolution options only makes the environment look sharper. Thankfully the sprites and textures were unchanged, so the game still has its distinctive look and feel. Its just clearer and controls better with a much smoother frame rate. The game does default to "smooth" textures which filters the textures and to be honest it looks like crap, so turn the textures on to "retro" and enjoy the timeless sprites the way they were meant to look.
This port is done right because it fixes what aged poorly while keeping everything else intact.
This port adds a couple of other things too. All those lovely Steam features were added into the game. Acheivements, steam workshop (which actually works very well) and easy to use online multiplayer add to the game in many ways.
The map community is actually pretty robust with hundreds of custom user made maps to download. Like the original DOS release this version comes with map editing tools so you can make your own (its very hard to use though due to its old age)
Sadly the multiplayer community is pretty much non existent. Though when you do find a group of people to play with the deathmatching is pretty fun. Its just hard to FIND anyone who wants to play multiplayer. To make things worse the netcode for the multiplayer is pretty much crap, when it works though multiplayer is a blast.
This version also comes with the 3 official expansions for the game. Nuclear Winter, Duke it out in D.C, and Lifes a Beach. These expansions are pretty fun for what they are but their levels aren't quite as good as the original. Its cool that they came with the game and they do add some value.
Overall I recommend you get this game, its old school FPS gameplay at its finest with some personallity that few shooters can beat. This is by far the best version of the game and if you want an unaltered version of the game this port comes with the original DOS Duke Nukem 3D that doesn't have steam attached meaning you can burn it to a disc and play it on a vintage PC like its 1996 again. This is the definitive version though and I strongly recommend it.