Something odd happens when the character turns his head at the end of the first video. His cheek just suddenly pops into being. Also, when he nods his head up and down it doesn't quite look right with the perspectives, but that could just be because there's nothing else in the scene for context. The running looks good.
This is truly amazing to me! Very expressive... I am a newbie, so the idea of a tutorial is really appealing, would love to see how this was put together!!!