Hey scarmy,
I think the biggest issue is the anatomy, it's all goofed up. Body wise, he is unbalanced and his right arm looks weird because it is totally in front of his body. At that angle, it would be partially behind his torso, and would not hang straight down like that. His left arm looks kind of confused on what it's doing, like it partially in a sling or something. His upper body is hunched over, and his head is too far foreward. I drew a skeleton over your guy to explain:
It was a bit difficult to tell where his waist was, because the purple/blue thing around that area is unreadable. I could not tell what it was, or where it was resting, so I just estimated. Then I drew my own skeleton to show how you could balance the pose more:
His upper body is hunching foreward in a non natural way, and his head is protruding forward off his neck, and his feet are sort of at the wrong angle from the rest of his body. Mine is not excellent, but the pose is more balanced. I kept the left arm how it was, because I assumed you had some purpose for it bring up there like that, either holding the cape, or in a sling, or holding a shield, or whatever. You have your guy about 6-7 heads tall, which is ok for an anime character like this.
As for facial anatomy, you have the "cut off skull" syndrome, where you are drawing the eyes too far up. The pupils should be halfway between the top of the head and the chin, the nose half way between the pupils and chin, and the mouth halfway between the nose and chin. Right now the eyes are between the top of his giant hair and his chin. I drew an approximate line halfway in the skeleton head, and you can see your guys eyes are clearly above it. Next, the top of the head looks flat. This seems to be because the "emo wave" thing in the front of the hair has a sharp curve in it, that makes it looks like it's falling over an edge. I'd also fix the eyes, one is way bigger then the other, and the bigger one should actually be smaller then the other one, if anything, because of the angle his face is at.
Lastly, I think you are abusing dithering. Especially on the neck, hair, and chest, you are dithering a lot but it is adding nothing to the piece, just making it look very noisy. I understand you are constraining yourself to a palette, but you don't always need to dither to make it look like there are more colors. Now that I look at it, the shading is kind of inconsistent as well. In the arm, the light is coming from above, yet on the face and neck it is coming directly at him, and again on the hair it is coming from above. Then, on the cape it is coming from behind him, sort of. The blue shoulder pad is kind of pillow shaded.
Good luck
