The course is great - much thanks for making it. The one extra thing I'd have liked there would be to see how you'd complete the mesh round the eyes, extruding inwards while keeping the vertices tidy and properly spaced. Most tutorials seem to run in the opposite direction, laying out the first vertices directly round the edge of the eye and then extruding outwards; working inwards looks like it'd give you less control and make it harder to keep vertices lined up above and below the eye.
Truth to tell, this is why I'm looking forward to Retopoflow getting the edge-patches tool. It looks like it has the best of both worlds, quickly filling in blocks of mesh while giving great close-in control of vertex spacing round eyes and other features. I'd camp outside your door in an ice-storm to beta-test that.