Yes, I listened to the whole thing. Twice.
This track is pretty much what I would have expected for this picture as far as ambience is concerned. My main issue is dynamics. Good ambient music has dynamics to it- functions through the three forms of musical evolution- transformation, combination, and elaboration.
Overall the track is basic. I think the message could have been expressed in a shorter work, something noted below by others. Ambient shouldn't really be synonymous with "long". It paints a picture, just like all other music, and when the painting is resolved enough that the viewer can understand it, it is done.
Additional instruments might add more detail and vary the piece to resemble a more natural cityscape feel. Think of the city- it isn't constant, it isn't linear. Traffic lights switch, new people walk by, a truck might roll in, or maybe an airplane might fly overhead. Take the time to stand on a street and see and hear the changes that occur there. Feel the way the sun interacts with the world- the motion of the clouds, the songs of the birds, the reverberance of the tall buildings. Notice the pedestrians- who are they? Where are they going? Where did they come from? In a piece about the city, I want to feel these things, sense these greater questions. They are the foundation of the ambiance of the cityscape.
The composition in this was quite basic, even for ambient. Some shimmery pads or little arp stuff might have benefitted the piece to create more harmonic and melodic texture. Different street sounds and other vehicles might create greater background texture.
Total: 49/100 (NG: 2.5 stars)