This looks really atmospheric, I have no idea of what fallout is but you can see from your work that it is some dark and forbidding place in the future.
I personally prefered the ground before the drybrush because it was so uncompromisingly dour which reflects the sort of world I think you are trying to portray. Although I would agree from an artistic point of view the dry brush works well.
Apart from the fact that I think your work is ace I like the feed back you are getting and using.
Very inspirational in a dark way
Keep it up