The way that the mist has been made on the bottom is amazing. It's unbelievably real and fitting to the piece. I like the light shining off the edges of the cliff and wolf, it's a good way to make them stand out more.
My criticism would be that I would have liked to have seen a little bit more detail on the moon. Maybe some faint craters so that it doesn't lose the amount of brightness it's meant to represent.
Still a great piece of art.