The nose is looking pretty good, one thing that's making the piece lose emotion is that the nose looks more or less like a relaxed nose when muscles in the face should be contorting it a bit. the nostrils could be flared more and could use more arch. Actually if you just grab a mirror and make a snarling face pay close attention to how the nose interacts with the rest of the face.

aside from that I'll wait to see more direction before saying too much maybe those eyes could go lower though. even though you may not be going for a photorealistic human, our minds have been filled with patterns and formulas for how things should look so loosely conforming to basic human proportions is often a good idea.

keep it coming, man.