The soft, smooth lighting of the background kind of clashes with the aliased, outlined elk. You've also got a lot of colors here that don't really add to the piece, which is a bit of a faux pas. This doesn't stop the actual art from being eye-catching and tasty, though.
Amazing colors! Especially the change into the fire effect at the bottom of the lights. I know it was a commission, but I can't help to imagine there is more to the picture. So that's my complaint to you... I want to see more! 
Good job! 
Nice!