I have no notes on the actual composition of the piece, which well overcompensates for the few anatomy issues that are present. One that stands out is the location of the crown of his hair. If your intent is for it to separate from the viewers middle left, usually, it's a line that goes from the hairline to the crown.
Your foreshortening works, everything else works, it's just the weird angle of the head, and where the crown of the hair is located on that sphere.
Wow. I'm shocked that you didn't lay into me about the perspective. :O I understand your points about the hair, but think it's harmless enough that it's not currently detracting from the piece. And, since he's channeling Spike Spiegel's hair style--apparently--it wouldn't do to make the part so well defined. (I guess it technically shouldn't be there at all!)

[edit] While i'm at it, i guess i'll make a brief swipe at the Klavier piece. You did bother to look at an actual guy with his shirt off when making that, no?
Guys have ribs. Unless he's a little plump, guys manboobs don't have a sillouette on the outside, especially when his arms are up.
But you are getting better. Proof being the looking up piece. What's the timeframe on the completion of that?
The Klavier picture is almost four months old. Forgive me when I say,
"It's behind me, darling!" 
And no, I didn't use reference, except for the pose, which came from
here. I already realize at this point that the picture is anatomically incorrect, but as long as the fangirls aren't complaining, I suppose that's alright in this case.

Also, I think it took about five days, working on and off in the evenings.