Congrats on your highest score in two challenges entered.
At first glance I see a very creative image. Your choice to shoot on a light background and invert to negative to give the appearance of the moon was a great one. I give the creative thought a 10 here. Technicals, exposure are fine.
As far as the score goes, 5.72 is not bad at all in an open challenge. The choice of background is probably what got you. Many people will give high votes if someone uses a background in the studio for portraits but are not as free with the high scores if an object is placed directly on a background. What is the difference? I just don't have an answer for that. I do think that it night have been better received if you had inverted a night shot, printed it out, placed the lens cap in the same spot as your current image, took the shot then inverted. This would actually make it look like a moon shining down on a landscape rather than a background.
Overall I think it's a great shot that you should be proud of.
Thanks for the opportunity to critique this image.