Hooray I got around to it. Nice little paintover.
http://www.geocities.com/katagarik/tien.txt
Here you go. Note: That is not an update as many people always seem to assume, it's just a crit made with paint. Anyways to the crits.
The facial crits are there so i'll move to the body. You have a fairly good understanding of the body and muscle groups, but you seem to be afraid of doing any real shading. So your skins lack depth and substance and rely on the mesh to support that. Bad signs ahead unless you learn to curve that.
Second, you don't have a colar bone! What happened? Probably just forgot because thats what alot of skinners do. Believe it or not the colar bone is a very important part to a shirtless character to make the skin sit right on them.
So play with your lighting and shading, message me on MSN or keep posting your work here for crits and i'll keep checking back. Lastly though, just have fun, remember you don't need to make him 100% like Tien, leave a little bit of your own flavour.
Edit * Oh and about the skin color that was just my choice, don't worry about changing your tone it's fine the way it is. I just chose a color and started working with it.