Hi!
first of all: great job. Looks very cool, i couldn't have done better.
now to the constructive critisism. 3 things:

1. The rotating with the mouse is way too fast. i just touch my mouse and he turns around twice. Not quite, but nearly
2. The "wire" texture that's used under the bridges could use some work. I'm not a level designer, and I don'T know what's wrong with it, but it looks weird... I wouldn't entirely change it, it's a cool idea, just work on it a bit.
3. I hate the elevater sound that comes with 3dgs...:D... sry... that's nothing against the 3DGS team or you, but I dislike the sound ... it doesn't really go with the doors... it... sounds weird. I think the sound should bedifferent. If you're keeping the sound you should make the doors a bit slower, because they are done moving half a second or so before the sound ends... shich is a bit to long.
But, as i said: GREAT job!!
keep it up.
I like your portfolio too... looks VERY cool

Micha