These 5 maps are from an unfinished TC that was to be named Duke Nukem Unleashed. They are for Duke version 1.3. You can play them as single maps or as an episode.
To play as an episode unzip all 5 files into a folder. Rename the maps as follows: UNLSAMP.map to e1l1.map, metro.map to e1l2.map, militarybase.map to e1l3.map, anlcity1.map to e1l4.map, and aliencity2.map to e1l5.map. Also rename tiles014.unl to tiles014 and tiles015.unl to tiles015. Then click on duke3d.exe and go to episode 1.