So, let's see... autoplay, splash screen, a video with no navigation controls. That site's UX sucks in a big way, so why is it #2 on HN?
So I don't think general UX/video guidelines apply in this case, even if they're valid for most cases for online video.
Sure, they should probably have used an adaptive bitrate video for users with poor connection, because here they can't pause and let the video prebuffer for a while. Other than that this is pretty impressive
You are applying heuristics that are true for man websites, but don't apply here. I would say this is more like a simple video game. It would make no sense for example to have navigation control over this video. That is the point, you can't just rewind to before the accident occurred.
EDIT: Not that I actually think its a bad UI. But either way its not always about the UI.