I'm pretty sure this thread has already been made, like TPG said (ninja). Anyways, just to comment on the city theme you've stuck up:
1) I would suggest going with a sort of warehouse theme more then the city theme. I say this because
-TF2 traditionally isn't very conducive to a bustling city theme, but an industrial theme is certainly plausible (I don't mean this like pipeline, I mean like an actual industrial district)
-The Half Life 2 props and lighting sort of detract from the theme.
That said, the map itself looks really interesting. I would also like to see some more texture regulation (for example the grating floor on the platform in picture 1). Also, you might want to consider changing the lighting to more 'regular' tones, bright blue just doesn't strike me as realistic.
Finally, for what it's worth, this map totally reminds me of BF2142.