Well lets start my mini commenting spree on your highest scoring challenge entry (to date!) I hope things don't just downhill from here lol.
The 180 degree flip literally turns this shot around! Pawns are nice and sharp and I like the fact the background goes from white to blue. The board doesn't look perfectly level and for me its niggling (slightly). A simple shot but often the hardest to execute well, its well thought out and executed :)
This picture is so striking. I'm really surprised that it didn't score much, much higher. It's so sharp and crisp, and well. . .just interesting to look at :)
this photo was very interesting but i'm not sure i like the fact that it's upstide down .. but the effect is pretty amazing and intriguing - i gave it an 8 though :)
A very nice example of the inversion idea. I think it works so well because of the extreme clarity in the reflections, and also the waterdrop/icicle like shape of the pawns... very nice! One thing I think might help this image is the changing the color balance to remove the excess yellow or just convert to b/w..