Bad rotoscoping.
People, this guy didn't draw everything himself. What he did was, he put a video of a well-known skateboarder in a layer, then he drawed lines over it. I've did that too once. However, I don't think rotoscoping and tracing, because it requires time, skills and effort to make it look right. However, this is badly done rotoscoping, and that sucks. The movement is great, but that's no surprise because it's rotoscoped. The drawings suck, because he didn't put enough effort into it.