Looking good. I like the way you've done the cliffs. One suggestion I have is to maybe reduce the mist at the top of the falls a bit so that you can see the water streaming over. Looks like some of the larger towers (upper wall and on that island) don't have shadows. Are there going to be bridges to the island estates? Or do they get there by boat? More rooftop color/brightness variation might be cool...but you may be planning to do that at a later stage. The textures look a little "noisy", but not sure if that's me and my screen or what. That's about all I've got! It's a neat map. I like the angular shapes of the city...it's kind of unique looking.
M