I'll explain: The Expansions are fine and all but the game itself is kindof broken.
"• You can't run usermaps through the menu directly with it while you could in the original jonof. Only when adding -map mapname.map in launch options by right clicking on the game in your library. Why removing that?
• Can't change music and SE volumes independantly. There is only one bar; You could do that in the original game in DOS. Why removing that?
• Musics stop for half a second at the end when looping instead of looping smoothly
• can't play the "+" version without opengl even though opengl fucks up shading
• mouse sensitivity setttings not precise enough : it's either too slow or too fast
• can't quicksave/quickload, have to go through the menu
• can't change HUD size on the fly, have to go through the menu"
^Copied from MetHY's post on Duke4.net Forums.
Basically: Stick to the GoG version for now until they fix these issues (Lets hope they fix that before the multiplayer comes in).
Taken from the steam store page:
"Duke Nukem 3D: Megaton Edition includes:
Duke Nukem 3D: Atomic Edition - All four officially released episodes of the iconic shooter with carefully restored visuals, timeless gameplay, and challenging Steam achievements. (OpenGL)
Duke Caribbean: Life's a Beach - Grab your water gun and sunscreen as Duke battles vacationing aliens in beach side hotels, tropical lagoons and even a cruise ship! (OpenGL)
Duke It Out in D.C. - Duke takes his special brand of politics to Washington D.C. to turn back the alien invasion set against the White House, the Lincoln Memorial, and even FBI headquarters. (OpenGL)
Duke: Nuclear Winter - Take a brutal walk through this winter wonderland as Duke gets into the holiday spirit by bringing the battle to the North Pole! (OpenGL)
Duke Nukem 3D Classic - The classic version of Duke Nukem 3D in all it's original glory. Hail to the King, baby! (DOSBox)
Hmm, it also seems that the expansions are only for the OpenGL version?