I agree with Max, looking at the grey area made me think *braaaainssss....* For me it doesn't look much like a natural settlement.

What does the grey vs brown signify? The organic look of the streets is potentially an interesting effect for a culture with some kind of magical biotech culture, but for an ordinary human city it's just a bit odd to the eye. I find it helps if I try to think what kind of information or effect I want to give the viewer, or what kind of information I'm trying to convey in a map.