I love the style of this map. Beautiful work!

The only improvement I possibly suggest is in the shadowing of the roofs and at the base of the buildings. On the roofs, it seems to me that the shade should be darkest on the back slopes facing directly away from the light source and lighter as they rotate towards the source. Also, it looks like there is a tiny shadow under each building but they seem to be orthagonal to the building base rather than pointing in the same direction - away from the light source. The effect is to make it difficult to tell from which direction the light is coming.

Looking forward to checking out more of your stuff.
M