I like the way their intersection with the walls makes the clouds explicitly 2-d. Very cool!

These are really cool.  They remind me of shoebox diaramas.

I like this serie very much <3 This one may be my favorite *u*

Thanks guys! :^) Yeah, I purposefully set them apart for that reason; putting them together would throw off the prespective.

Very good. Original.

These are well executed. I do think they could use some antialiasing but they are good none-the-less.

 I like these :] Also I think putting them in the same file would  distract from the cool depth they have. 

 I think you should put habitat 1, 2 and 3 in the same file