Newgrounds loop player: http://www.newgrounds.com/audio/listen/746371
I had originally wanted to flesh out the inside of the city's music more and make a kind of slums feel to accompany between the alleys and factory floor, but it ended up feeling more at home topping off the Crystal Mines in the end. Regardless, I'm still content with how it came out, and loops fairly well.
update toned down the bass on this piece as well.