I like the concept
. The colors almost feel too bright right now. The trophy head doesn't seem to be hanging, but rather floating--moving the head part closer to the body and dropping it down a bit should help.
The blood coming from the head seems too faint and bright.
The form definition, especially in the muscles in the arms and belly, is really lacking...anatomical reference might do wonders, like Adarias said.
The fabrics and fuzzies are lit...well they aren't lit
It makes it feel very flat at those parts.
The metal in the helmet and bracelets could use higher contrast and shine to give a "metallic" feel, you know?