Looks really nice, however if I were to give some constructive criticism... I would say that you should either make the pants bigger, or curve the lower body to fit with the pants; because it looks kind of disproportionate. Also it seems that some of the body parts smooth shading looks a bit weird, I don't know how to say it but some people would get what I mean. (Unless i'm the only one ;-;)
But still, the HD Blockhead model looks really cool, great job!