This just floored me when I browsed through "critiqueable". I couldn't believe it was a photomanipulation--I thought it was some happy accident of nature.
Originality, technique, and impact are just full marks. The margin and the spacing, the area of breathing around the focus of the image, the impact are all amazing.
The only thing I'd suggest is maybe adding a bump near the back for the tail. Also, I think the nose of the horse needs to be a little bit longer and flatter--it took me a few seconds to figure out what was "off" about the picture before me.
This is a win on so many levels! If you were going for something to catch people's eyes then you have succeeded! This is an amazing picture and I still cant buy that it's artificially made, you did a great job with it. The colors have a wonderful rhythm fading from dark to bright leading our eyes to the head of the horse as he gallops out of the cloud. The sun rays coming out from behind at the top right where the Horse's back is could have been brighter but even that is forgivable with such an amazing piece.