There's something odd going on with the south bank of the river, inside the city - the shadow is like you mean the shoreline to be a cliff or sharp embankment maybe? And if you mean the two hills to drop off sharply toward the water, I'd kind of expect no shadow strip next to their bits of shoreline.

Are there going to be docks of some sort, or does this city turn its back on the river?

The gold building (?) in the middle - it seems to have too little shadow. Unless it's really flat?

The crenellations on the castle towers are out of scale. Unless you intend shooting ballistae instead of bows :-), the slots are as big as your smallest buildings. Normally you'd see slots a foot or two wide, three max?

I agree - the buildings are nice. How'd you generate them?

Good job with the groundcover - random and gradient - placed, instead of tiled.