i would take a second look at the shoulder area. Try to pin point the scapula, clavicle and acromion process and seperate them from your deltoid and trapezius. This should give you a much better result on your shoulders.
define your character’s rib cage too, as it would effect how you would sculpt your serratus muscles.
i would smooth out the connection between the bicep and forearm.
other than that the model seems to be heading to a pretty good direction, and judging from your previous works, it should turn out pretty awesome but the shoulders are really bugging me…it’s effecting the silhouette of your model.