the thing is, valve cant count to 3. DX if youve ever play the DLC maps on portal 2 two player and finished it, you would believe that there was going to be a 3rd one. here is the ending of the DLC maps [link] make sure you watch the ENTIRE vid in order to fully understand.
I love the lighting but the walls and GLaDOS are a little too reflective... it really takes away from the sense of it being real and makes it look like just another 3D render. Maybe tone it down and add some dirt or maybe scorch marks or something?