Seconding the 'too defined' motion. I can see that you put a lot of effort in this, but in art, knowing what details to leave out takes more knowledge and skill than trying to detail everything in. Always step back and look at the whole painting, decide if your details are adding more value to the overall composition or whether it takes a way from it.
Anyway, the colors are pleasant to look at, and it is a good effort. Paint more and become better as you go. Good luck!
Wonder how the residents get up and down? Are there tunnels and stairways winding up through the rock, or perhaps elevators? Maybe there's a cable car that goes from that little hill to the left, or a balloon service, or...
Alright, I'm probably thinking too hard about this. I'll just say that it's an incredible piece, and you did well!
I like to leave these things up to the viewer, though my thought process was that this area is situated between two tectonic plates and the islands have been pushed out of the water by those forces, after which the houses up on the cliffs were abandoned. And thanks for the kind words!