Good idea and nice detail in this shot. The main thing that I think lets it down is that harsh light causing those heavy shadows and the falloff top left is quite distracting.
I'm sure you're getting 'poor little fellow' comments. :) It's a good thing turtles are made to flip themselves back over. He's perfectly in focus. I wish the grass weren't so high contrasty... it's making this a bit too busy for me, I think. Nice and sharp on his eye. That couldn't have been easy if he was struggling to right himself as I suspect.