I don't know exactly how humanoid it's supposed to be, but the torso looks a little strange. With the way the chest is shaped now it seems like the medallion like thing is in place of muscle than resting on top of the pectorals. I'd try not to round them out so much, and imply that they go under the medal. That, or just flatten out the shadows a little more.
Also, it wouldn't hurt to add a little more torso at the top of the abdomen. Typically, when standing like that, some ribcage is jutted out a little, and the shape/shading you have now just below the chest doesn't really convey depth
my (very rough) edit on the left to show you what I mean.
EDIT: One more thing! You might want to consider adding a little of the outline color or some darker value to the chin/neck--maybe even a little bit of an outline to show the chin jutting out at that angle
really love the dithering!
Also, it wouldn't hurt to add a little more torso at the top of the abdomen. Typically, when standing like that, some ribcage is jutted out a little, and the shape/shading you have now just below the chest doesn't really convey depth
my (very rough) edit on the left to show you what I mean.
EDIT: One more thing! You might want to consider adding a little of the outline color or some darker value to the chin/neck--maybe even a little bit of an outline to show the chin jutting out at that angle
really love the dithering!