looks interesting

why does the sky have a shadow? (i'm assuming the blue background in the first shot was a sky, not a wall) you can make it not receive shadows if you turn it off 'receive shadows' the render stats in the attributes editor. or you could just assign a... i forget the name of the shader...

the textures look stretched on the roofs (you will need to tweak your UVs)

the buildings also look very flat... perhaps assign a bump/normal/displacement map (normal map should do you good if you can figure out how to generate one)

what time of the day are these shots meant to be in?