Looking pretty cool so far! :) I feel like the head is too far forward on the neck; Notice how part of the skull "hangs off" the back. In yours it looks like it slopes from the neck forward to the top of the head.
the flat forehead is intended. It works in my drawings, so i hope to get it to work in 3D. I might play around with it a bit (after all th head became a lot broader than it was supposed to, it might have broken my design). I fixed the sloping from head to neck by making the skull longer. Incidentally it rounded out the…