This concept piece is both visually and mentally appealing.
I found that after looking at the image for a while, I'd completely discarded my initial thoughts about it because I found more in the image than what meets the eye.
Initially, I was under the impression that the area in the image was desolate and destroyed; Looking at the picture a little longer, I got the feeling that perhaps there was a something more ominous we, the audience/viewers, aren't directly aware of.
I felt that there could have been things living here that we aren't able to see in the illustration-- beasts and things we often see in video games or movies, for example, that scare the pants off of us, or leave us feeling afraid for the protagonist(s).
I say this because my imagination sees structures (the marked stones and the distant bridge, etc), and personally I feel that means some sort of civilization.
I found that this was almost ingenious because the viewer is not distracted looking at the creatures or beings living there, but can still be aware that there is something to be found here.
My eyes were immediately drawn to two things:
1. First was the marked stones in the bottom left corner, which is almost unfortunate. While red and black make very good contrast, It feels like it's too distracting in the piece. At first I was going to recommend you change the red to blue, but then I realized that there was also meaning to the color as well. The red seems evil and ominous, just like the rest of the piece, while blue may seem to peaceful.
However, the problem of it being too distracting is still there because the red and black make such a large contrast.
This is unfortunate because your eyes are drawn away from things like the water, and other stones nearby, as well as the fog (which I, notably, didn't notice until I took more time to study the water and the are down low).
2. Secondly, I noticed the dragon almost immediately after. Unlike the stones, the dragon seems to fit in much better with the piece, and the flames coming from its mouth also bare a large contrast, which helps to bring the dragon forward.
As opposed to the stones, this sort of distraction is a better one-- since I feel like the dragon could very well be the centerpiece of the picture itself.
While the layout is very important, the dragon itself tells us that there is some story about the area-- that there is life, and that perhaps it could be the reason the area is destroyed, etc.
Two last things I felt I should mention was that: 1. I'm very in love with the stone structures in this image. The way they open like mouths and dip together allows the audience to get a better view of the darkened sky, and lets us see that there isn't much beyond-- and if there is, it's all hidden in fog.
I also love that you added more marked stones in the top left corner to give the ones at the bottom left more meaning than we first see (or vise versa if you put the ones at the top first).
2. I really love how the color palette gives off so much mood and feeling.