Ok, first head is a Tau-ish Soldier, depth of the head overall is good, but then you look close and boom, light spots in weird places, map the head and proyect a imaginari light and see where shadows will cast. Also, bolts are way too 2D (I know it's WIP or whatever), and I don't recommend you to do something mapped that way, avoid it if you want, making it face to the camera, remember that it's mapped to a sphere, it's pointless to make details that you have to look from a weird angle. I'm not telling you to not doing it, just make it more natural. I'm pretty sure you know how to work on everything else.
The Draugr has better colouring work, more natural, but again, work on your lights and shadows, the horns don't have the pop-out effect they should have, maybe darker shadows will help. Other thing you did with the other head too is the light source, from what I see from the front, the light come from the top, but then you see the top and it has no light, like you forget about the top of the head. Remember that you are working on the same material as the front. Mouth needed more depth overall, but that's all.
Anyways, good progress, keep working.