this might also help
From The Lost Media Wiki
okay so new strategy, has anyone tried using the google inspect thingy on the internet archive post? I'm pretty sure we could remove the little "nuh uh u need an account to watch thisđ¤âď¸" and either watch the video or find the video file and download it. I've tried this but i know absolutely nothing about using the google inspect thing so if anyone has more experience this might be useful^^
ps: here's the internet archive link if you don't have it https://web.archive.org/web/20180220175746/https://www.nicovideo.jp/watch/sm13822734