From one MIchael Luscombe to another, I think they look great!

shuttle concept is cool

I was thinking that the Sewer image actually looks more like some power station, or goverment lab than some old filthy sewer, but I still like the cold steril look.

I like the idea of a clean sewer.
Holoda's head is really awsome, but his chest muscles look too much like boobs.

Your checker plate flooring is scaled to big in 'Sewer'. I have some good maps if you want them....

I like your shuttle best, but it needs a background.