Well, first off let me tell you that the idea for this is truly incredible.
Put more effort into the planet.
The walls and oher painted stuff looks like a good basis for TONS of detail that you could add.
Add tiny little details in that part under the arch. That could be a city far away...
Stars? Add them up top. ^.^
I really think this piece has so much potential it is incredible, just never stop adding detail to it, it could become something of pure wonder.
looks nice to me i love the dark figure contrasting with the BG. love the colors and composition. but i think you could have put some more detail into the clouds and the rock(?) walls, they look flat when i compare them with the planet in the BG.
but if you gave the planet that "painty" texture you gave to the rest, that'd be nice too.