Coming along nicely. Very good!
The walls look alot better... I think the stones look a bit too smooth, try adding some noise to the color.
If you got a wood or stone floor texture hidden away somewhere, it should look nice on the top of the towers..
Looks like you went with the motion blur shadow variant.. looks good, but if i can nit pick a bit you could move the shadow 1-2px up and to the left. I think you got a couple of pixels outside the center of the blur.