Well! First of all, a nude! How refreshing to see.
The torso has great definition of muscles, but not overly defined. Sometimes I find people shade them too much and make a six pack that could cut steel. Proportion-wise, Sasha is pretty darn good. His head is a little bit big, but not by much and perhaps the feet could be bigger but other than that you're dandy.
Colouring is always hard. I struggle with that on a daily basis. Maybe you could think about where your light source is? You do have shading in there but if you like you could try to go darker, and think about body parts that may cast shadows across the body due to said light source. The hair is lovely. But then could also again have a little bit of depth by having some darker bits in it.
Really the way you have coloured is complete within itself, it all works together. What I'm suggesting is just another option of many of colouring.