Awesome work! I love your sketches and the mount is crazy awesome (really nice dynamic pose too!) If you're interested in any critique I'd maybe suggest pushing the lighting and contrast a little more to try and separate your values and forms a little. A nice test is to greyscale a thumbnail sized version of your image (or just zoom out) and see if the forms still read. A quick test with your final image and I feel like if you just lighten up your background a touch with some soft brush work and maybe darken your foreground values it should read a lot clearer!
Good luck! 
