Good Luck on doing your masters
I like the colors you used-really nice....I just have a few suggestions:
This character's head appears too big comparing to the rest of this body
His elbows are too high, they should be able to touch his waistline
His hands are too small
I would also define his 6 pack more, so that he looks more powerful
The blades on his back should be more reflective, as metal is so very shiny, you look like you made duplicates of the same blade all over, which subtracts from making it more interesting.
I really think your shadows on his body are quite good, liking your work!
Hope this small crit helps
*There is always room for improvement*