ooh, this is really nice. Is there going to be a background or is this as far as you're going? Either way, I really like how this came out. Some things that could use a little tweaking though, are your colour choices. Very the hues for your shadows and highlights more. The claws on it's left paw seem a little long compared to the right, too. Last thing that sticks out to me, is the AA on his small teeth on the upper section of his jaw could use another buffer shade.
Be sure to post some more.