I'm not saying you're doing anything wrong, so everything's fine. But I can't help but notice that the details of the robot body really should be more symmetrical, whereas the head doesn't necessarily have to be. Since the Terminator has the appearance of a specific person, and that person almost certainly doesn't have perfectly symmetrical facial features, their skull isn't symmetrical either. This means that to replicate the shape of a person's face, Skynet would have had to create slightly asymmetrical skulls for each appearance. Even Arnold has a very asymmetrical face, remember how crooked his glasses were in T2. I also like the idea that all the differences in Terminator skulls are just features of their construction under the biological shell (the human appearance they were mimicking), which explains why Terminator skulls in the universe differ from each other.
Moreover, I'm very interested in observing your work, and I would like to see its progress more often. You have a very pleasant mesh topology. I myself have been wanting to start retopologizing my skull for a long time (when I finish its more accurate version), ensuring that its topology is correct so that the surface is smooth without dents when smoothed. I wonder, based on which skull your skull is made, and what are its temple details?
