Lichens

Let me begin by saying that I enjoy your portfolio, and I've returned to look on several occasions. (I'm particularly taken by "Wormwood and the chain", but you already have plenty of feedback on that one.) However, there are a few things I suggest changing about this image:

First, although there is a lot of detail, there's not much to draw my eye other than a bulls-eye in the center. I'm left wanting more pattern or leading lines or definable objects or something. Oddly, I am called to investigate the shape of the rock and growths when I cover the bulls-eye. Maybe the center is just too overpowering in comparison to the smaller features.

Second, the orange/yellow details look a little fuzzy to my eye. Look along the left side of the large version. Do you agree? Maybe a little selective USM could help.

Third, the light is pretty harsh. You got good color, but the lighting contributes to the flattening. Diffusing might help.