Amazing environment!! That is a really cool castle. I like the way you used light and value in this painting... this makes me want to hurry up and start working digitally so I can learn to do environments.
This picture is so damn MTG. I could almost name some white spell this fits to. What I didn't yet say: Amazing work. I wished I was that good with architecture. Or colors. Or perspective, or light, or composition, or value, and I even can't draw that shadow of that horse. Damn horses.