Actually, I think what Eero meant was you have too many vanishing points. In perspective art, you have three kinds of perspective: 1, 2, or 3 vanishing points. A vanishing point is a point where, if you drew lines of infinite length across all the straight edges in a world, they'll meet at a point. Obviously, because we live in a 3D world, the three points should be distinctly for length, width, and height of an object. It may be that the perspective of your buildings don't all meet at the same point. I personally wouldn't know...I haven't checked it myself, although I did notice that, on the right hand building, it seems as though your door jam is "crooked". Course I could be wrong about that.
