Nice idea and perspective, but I'd fix colors and exposure a bit. Add a little contrast, it's kinda washed out, but besides that it's great.

great work

Looks better now =)

Love the mood of this, perhaps if some of the further elements had some blur to it...it would give this some more depth.

There's one light source on the moons, and another reflecting from the moons. Since the moons are reflecting the main light source, the shadows of the "towers" should be at the same angle as the light on the moons because the light source from left is stronger.
Anyway, it's still a nice image...

great colours... love the planets in the sky