hmm, dont really impress me, but dont worry, its getting better with every map.
At first: things are too straight, its just lines and no real comicstyle.
Second point is that 2/3 of the map are buildings, no place to hide you could kick 10 hedges into water from top of that big, grey building in the middle...

It's a nice map, but I agree with Thomas about the grey building. How about adding some more buildings to block the way and add a little land around the edge. Like a small park or something. That's my opinion. And here's a tip for map editing, Holding down the shift key will make your lines straight.