I have great hopes for the TF2 mapping scene. The screens look very solid, even in this early stage.

What I miss from the screens is probably the red/blue color for the base walls. Maybe adding some yellowish tones to the spotlights might also give the map's visuals more atmosphere. The map's definitely in need of color.

I am only judging by the screenshots (dont have TF2 )-: ), but from them i would say that the map looks very crisp, very clean, well-produced, with wide open space for gameplay flow. Here are my crits so far:

The textures are super bland and flat, making the spots of flair you have added (support beams, window frames, signs, light fixtures, etc) look out of place. Like they just appeared out of nowhere, rather than naturally being part of the map. The lighting is also very flat, adding to this. I think that I can see the underlying style you are going for - big open clean industrial spaces. Some great maps that do this theme well and get the lighting and textures right are the tram intro sequence in HL1 and Sulsa's HL1 map Chaocity3, maybe check those for references.

I can't really comment much more without seeing more of the map, good luck.

This is already looks better than any of the custom map i have played thus far on TF2.