Yeah, that sewer level is really hot.
I think my only crit would be to remain aware of the texture placement, the grubby bit at the bottom of the brick texture looks great when it's on a flat wall, but not so good when applied across an arched ceiling. Perhaps you should alter it so you have a few variants of the same texture:
Standard (for flat walls, has a grubby bit at the bottom)
Plain (just bricks, no grungy edges)
Messy (has grungy edges on 2 sides)
That way you can better match the texture to the object it is applied to. This is small though and easily rectified. Ither than that I think this is looking fantastic. I'm really looking forward to seeing it in action!
All the best
Butters