I like how isolationist the picture is... I can't tell whether that was intentional or not, but it's really bold. The only issue I have is that some of the buildings seem to be somewhat blurred (note that I'm still giving you 4.5 because I suck at drawing buildings and this is still quite detailed in and of itself). The clouds also provide an interesting looming symbolism as juxtaposed to the giant wall bearing down on the city.