@GMW:
Tremdizzy: Very original and looks good. Unfortunately it also looks easily abusable (shooting players off, blocking paths, etc.)
Vaults of Haze: The closest use of good gameplay fog I can recall is the foggy alien base in Flap. Unless your map isn't high on details or shaders, I suspect performance issues may arise (fog forces the engine to redraw everything affected by it). The concept is interesting though.
Whiteout: I'm not sure if this'll work. Firstly open maps are human bias (even with jetpacks disabled) and can cause performance issues. Second the theme you've chosen is the exact opposite of what most mappers aim to avoid: monotony. Thirdly bright maps can cause eye strain (see K66's latest dev shot). Again the concept is quite interesting, but there are consequences to gameplay.
@K66:
I have to agree with CreatureofHell. The new one is way too bright.
Perhaps make the liquid from the old one look more like the radioactive slime in the second whilst keeping the lighting?
Maintenance corridor looks good. With some extra textures (which I'm sure you will add), it'll look even better. Good stuff.
@Spork:
I'm sure you're aware the stairs and the centre piece float, so you'll want to fix that.
The fog could do some recolouring. Perhaps some blue/green fog to match the blue generator? Maybe even just darkness like the pits in Arachnid2.
The double cylinder pipes are a new sight for me. I can't tell if you've done it from the screenshot, but you may want to add some kind of geometry between where the pipes touch the centre piece and the boxes to improve aesthetics.
