What first captures me here is the patterns that the dunes and hills make. Its a repitition yet, different. It holds the viewer and refuses to let go.
Secondly, as asjachyld put it, the textures of the mounds are wonderful, you want to reach out and touch it. For some reason I am reminded on a velvet piece of cloth, casually laid out.
Third that caught my eye was the small horiztonal extension in the center of the image. Looks like a walkpath, but reguardless, it adds a nice compositional element of a leading line to photomosaic without calling out too much attention to itself.
What I do not like is the hazy background, but its overall cyan color is much more cooler and doesn't hold the eye as long, letting the eyes go back to the midground and its wonderful hills.
Finally, just want to say wonderful job on the stiching together. I looked for a good while to try and find an error, but I could not.
Did see ONE thing though. On the bottom left corner, second hill over you can see the reside of a lens flare. Not sure if you caught that or not.
Whoa, this is beautiful. I cant tell where the first couple shots are stitched together, even the shadows are complex enough to hide where you blended them. I'm guessing it was at the first dark mountain on the right to the second row down of craggy rocks on the left where you cut. Just a guess, but that's where I'd think they were cut.