That REALLY reminds me of Elysion Skytown from Metroid Prime 3, was that your reference?. All you gotta do is get some more light sources in there and it will look really sexy. Some really nice brushwork though, regardless of how symmetrical and linear it may be. You should consider adding complicated machinery in there, something like big gears on the walls or ceiling. That would really look cool.
Meow, your map looks awesome, but the strider just kills the mood for me to be honest. I don't feel very happy seeing a 3-legged, bio-mechanic creature that was designed by an alien race to tear whole cities apart, whilst impaling citizens with its feet. I think it would be better to not have it there.
As for me, I'm going to try something out with my map and see how it looks. I'll post some screenies to see what you all think, but it's not "official progress."
edit:What do you think? I was curious to see how it would look at night. I think it looks cooler, but I don't know if it accommodates the theme well enough. I staved from giving it a "sinister" look, and I did some warmer colors instead of a bunch of green and light blue.