Very interesting image. But I think you have a small problem lack of shadows. As stated in your comments during the challenge it appears to be more of a silhouette than a shadow. I sat here and thought a minute of what you were doing and I understand that it is a shadow but I do believe most voters thought it was silhouette.
The composition is good and your lighting technic made this interesting. Just think that the absents of obvious shadows hurt you greatly.
I just relooked at this, it's a case where the thumbnail looks better than the actual photo. Gave a 3 originally, but I'm raising it to a 6. The reason it's not higher is because the colors look oversaturated and it's not a shadow but a silhouette.