The ridge on the head should be completely round and not blocky.
Update, I fixed the shape of the bumps, and added more depth to them. Any other problems before I start the face?
It still looks blocky. The small square near the forehead looks smaller than the light blue... thing. The pointy thing looks misplaced. Also, I think the shine shouldn't be there, it's contradicting with the ear-thing.
The helmet itself is smaller than the decorations on it. You should have done the head first to be able to get the dimensions of the helmet right.