I noticed your lights in the blue level are turning that weird black bluish colour. Almost inverting if that makes sense.. are you using a time, sin and cosine node? if so you might want to play around with your values so they don't get all freaky like they are. If that doesn't work you might want to try adding a constant clamping to the end of your string of nodes. Values of 0 & 1 should fix that.
I'm not much of a level designer so I won't bother trying to crit on something I'm not that strong in. From an artist standpoint some of the textures are showing kind of flat and in some cases stretched a bit, especially in the first and a little in the last two. Maybe try playing with your normal or specular maps to help things pop out at bit better.
hope this helps!