eduke32 is an updated port (to modern OS’s) of duke nukem 3d. i’ve just been messing around with it recently. the original duke nukem 3d data file needed is “duke3d.grp”.
to get the video settings to look good, go to video setup (in-game) and change the texture filter setting to either linear or nearest. linear looks smoother, while nearest looks closer to a classic duke nukem 3d look.

also you can get new high quality textures from here: http://hrp.duke4.net/
the new textures look amazing… however when using this mode on my pentium4 machine, the game was so slow it was unplayable. so something beyond the p4/AGP video card era  is most likely required.

info from these pages: http://www.gog.com/en/forum/duke_nukem_series/eduke32_text_illegible_or_fuzzy_or_blurry_or_clipped
http://wiki.eduke32.com/wiki/Frequently_Asked_Questions