Greetings from the critique club! I missed this one when looking through the Zodiac challenge - first impression, I like it very much. Looking a little closer, I have to agree with many of your commenters - the shadow of the back twin is really needs to go. I'm thinking that a little bit of backlighting (just off to the side) and behind the back figure might have eliminated the shadow and allowed for a little more sharpness for that figure as well. Overall, I think the exposure was very well done (better than most of my indoor shots!) and I'm surprised that this didn't do better!
Great DOF usage. Good theme exploration. I had an issue about the shadow behind the black piece. To me this shadow must be removed. Using a second light on the background you can do it. Or simple put the objects more distant of background.