Hmm. I really like this piece, but can't seem to find depth of field playing any role in it. The only part somehow blurred is the gray thing in the bottom but it too has some high frequency portions. Though I'm a bit confused about the subject of the art I still think it's a great piece, one of your better.
An additional minor thing: the aa at the rightmost block seems a bit banded.
Very nice job on the floor thing.