Negative:
Concerning the terrain, the most interesting terrain feature is the towers. But the group in the center of the image is all but completely black, It creates a very uncomfortable negative space, and compositional imbalance. The Blacks are to black.
The towers in the distance look much better!
Given the sky, I would say you should have no problem justifying a new light, to illuminate the towers in the center better.
The sky/background image is great. But the transition from one side to the other feels just a little too abrupt.
Positive:
You have a clearly distinct and attractive style in your images. This one is no exception. Its a beauty with just a few problems.
Great science fiction with a clear love for the golden age. I like it.