Hrm... Looks luffy.

Some crits: The ground is too bright, should be more dusk/dawn shadows, especially on the lower parts of the hills. The shadows of the rocks should be longer, as well.

The other thing is that the rock on the horizon by the sun looks friggin huge. If it is so far away that the base of it is past the horizion, then it is hard to get the size right, but if that rock is about the same size as the others, then it should be drawn smaller.

Oh, and there should be more fireflies.