CurtSquirt's map doesn't seem to be particularly dark, but I guess it's the forts that count, and you have two of them here, sure enough, at either end of the indoor arena. I don't think the texture work is going to win prizes, and you do have some rather steep sets of stairs that don't quite link to the upper level as comfortably as one might wish, but the general design is suitably cunning. Most of the space between the two sniping-ends is taken up by a pair of swimming pools, which is nice (though I would want more than a doubler in there to dive in very often!), while there are "rat runs" at the sides to make it pretty easy to sneak up on the enemy - unless they are waiting for you down there!
The main claim to fame for this map, however, is that Curt has made a version which can be used with the demo; get it from his site, and then unzip the map to c:\program files\atari\ nerfdemo\maps and the texture to c:\program files\nerfdemo\textures. There are some things that that version does not have, with floating lozenges pointing out what is "not available" - but if you only run the demo, you won't be worried by that! The "full version" version does not have an extra texture file, as we already have the textures needed.
So, a good start for a new mapmaker, with more than one clever idea on show. I am expecting great things from Curt's future productions!
And a similar view in the demo version!