Nice technique but your humans always look inflated and flat the same time. I mean you draw well but result isn't nice to see. Try to add much more shadows and lights and don't make corners but curves in places where parts connect. Also imho skin may be more 'yellow' and nose more bulge - now it looks like vertical cylinder.
Sorry I'm criticise. I't's easier to speak tI hope you'll understand what's wrong.
Eu tinha visto na Pixelaria, LINDO ;)