the top of his head is weird, the hair comes too far away, like... it looks like hes wearing a helmet rather than hair. shows his skull is deformed or isnt built properly.
the top of his gi looks very tight. theres no baggy or signs that it would be comfortable to fight in... while the polies flow well, theres some that arent really doing anything. moves some verts arround to show how real clothes would sit on a person.
the arms are way too high poly for the ammount of definition there. they are way too cylindrical, and very basic. the biceps look horribly unnattural... i would suggest reading my tut in the sticky section. but thats up to you.
the legs. same advice as for his top. and for his feet. they arent long enough, he has lil stubby feet on your model. bring the end forward a little. and then add another edge loop to show where the foot would deform when walking/running.