The tubes coming out of his head, why don't we see them on side view and how come we can see the 'hole' on both front and back view?
Side view head, maybe more hair at the back. Check up on some diagrams on head, I could be wrong.
Back view - maybe some pixels to hint at shoulder blades. Actually the part is on the wrong side I think relative to front.
The highlights on face - its not a good color - you should have it closer to the hue of the other skin shades. Also, I don't think it fits with the light source always (eg. on side veiw, i'd remove them all except maybe on the tip of the nose. Eyebrows- shouldn't the lighter yellow be on the top?
Moustacheod-polarbear-chicken-shark: quite inventive - it doesn't work for me for some reason. My opinion with drawing these types of creatures - you should be able to imagine how a human could evolve into a creature like this. Also, you should have things figured out like how it will balance etc. So, I would suggest wider shoulders so its balanced. Also, the tail bit should be quite thick at the shoulders, then taper thinner, but not too quickly - you have to fit guts in there somewhere. A creature with a mouth that big makes me think carnivore - so put the eyes on the front. I'd lose the shark fin - to my knowledge you don't get things like that for mammmals (where did the bones come from) and what purpose would it serve. Then again, guess its supposed to be cartoony and funny, so u can forget about what i said, just consider if u do more serious type pic.
