Nice.
I think the colors you used for shading are kind of monotone (the same colors throughout the entire map; I could possibly even guess at the small 4- or 5-color palette used). The scenery-gfx rock; the fog effect at the bottom and the trees fit very nicely, and even the moon goes well with the level.
For the layout, the only thing I have to complain about is that there are a bunch of boulders floating over a passage which stretches almost flat except for a few bumps here & there for the entire bottom of the map. It would be great if the bottom section rose in the middle and annexed that bottom-central rock as part of the lower terrain.
If you would use more variation for vertex colors, and possibly give the hill in the bottom-central of the map as I suggest, I would deem it good for release
Nice job.