Ruined city pics

Since the first pic i posted, to this one i've added a further layer of rocks behind the foreground ones, and started blocking in the shapes for the ruins of the city.

I wanted the ruins to be a lighter shade so i could add more shading to them quickly and they stand out against the rocks in the foreground.

To this pic, i added some mountains in the background to give it some depth. The mountains were a bit of a challenge to get right in the background and i messed up my layers a bit so the ruins shapes were being hidden by the mountain layer. But i managed to get it sorted.

This one, i used overlays to get the colour on the rocks and ruins. I built it up starting with the dark tones and laying the light ontop. To me, i think the rocks seem a bit dark, so i'm going to try and lighten them but without taking away from what's in the background. I also wasn't too sure about the colour of the ruins, but by adding more green tones, and a subtle blend of brown i managed to darken them down a bit. I also added cracks and texture to the rocks as they looked too plain.

This one, i added an overlay to the mountains to give them a purply colour. I also added snow to the top, which doesn't quite sit right on it at the moment as im still working on it. I also want to add some blue tones to it.

Is there anything else i can do to the ruins, coz something about them is bugging me and i dont know what it is? Also, i know i need a background heh.