Nice, I like the soft feel to this!
Dude it's beautiful. I don't mean to gush here, but nothing inspires me to get better at mapping and tablet work than looking at your stuff.
Really great! Want to see the rest of the castle!
Very much like how you did the chasm effect. I will have to work on replicating that. The land 'blobs' of rock seems fairly straight forward and cool. Did you draw in the crenelations by hand or was there some cool short cut? I like the detail of the placed stone along the walls and tower elements. Sketched in on your tablet and set to a low opacity?
Overall I like the design. It suggests that someone was just building into the terrain rather than trying to terraform it to fit their design for a castle.
Larger copies of my maps located on flickr and can be used for your enjoyment.