Consider adding some kind of video-like control on the page to restart the screencast; I opened the tab in the background, and by the time I saw it it had already gone halfway through the screencast. I eneded up refreshing the page to see it from the beginning.
There's (usually) no censorship in HN, you are just getting downvoted, most likely because folks think your comment is impolite, uncalled for, and brings nothing to the conversation.
I would guess he recorded his keystrokes and then played them back with a timer? Totally a guess, I did something similar in that manner for a canvas game demo.