The killing parts of Piranha Plant in the original Super Mario Bros. are actually the stem and leaves not their teeth or mouth. Do you know how misleading that is? You can literally jump through their mouths.
Everything in this video is possible. I have seen it.
That is the original game.
Then came Melee another official game. Brawl does not have the same proportions as this game.
Then we have Project M which is more proportional to Melee then Brawl ever was. So which one has the correct proportion? Both actually. Project M has official Sakurai Melee proportions and Brawl has official Sakurai proportions. So I have no idea what you are talking about. Melee is just as official as Brawl.