You're right about his head size in relation to his torso, I was referring to the size of his head compared to his body size as a whole. But yeah, if you chopped off everything from his pelvis down, and his arms, and left him as "Torso/head man" then his head would be in correct proportion to what you had left.
As a whole it's not too bad though, I like the feel of it. Something else that you might want to watch is your shading. It doesn't really feel like it has a good light source, like a 3D guy. It feels like a painting...if that makes sense. Not in that it looks 2D, but it doesn't look like he's really THERE in the enviornment due to his awkward shadowing. Something I MIGHT be right on is that the shadows in several places look too dark, be very careful when it comes to dark shadows---black is not a good thing, and if you're using the burn tool, be careful not to overdo it in spots. Right now you can't really find a lightsource. Something I'm learning to work with is putting down a base color inside an outline, and then taking a highlight and a shadow color (never using black), then slowly adding inbetween shades. I assume this is common, and it's helping me personally to figure out lighting a lot easier.