I love the look of all your maps except "The Divide" and "Project 2012." I specifically like the ominous feeling that "On Throughout The Night" has and the base design and the look of "Dune." Although I can't see any side route possibilities for Dune from the screenshot alone and the upper right...
My little brother showed me this. It makes me want to buy myself Portal 2 as a late Christmas present for myself, assuming noone else gets it for me. Merry Xmas for all