Furious Paul sets new Castlevania World Record

That's actually an old world record he did a while back. There's two records ahead of his now with his time being the third fastest.

its basically value overwriting, being on stairs is a value that prevents knockback, getting hit is a value, dealing damage is a value, something in there confuses the game and instead of returning the normal value of boss takes x damage it takes glitched y damage, at least thats what i get from watching this, theres a similar form of value manipulation called ACE where you manipulate a bunch of values to glitch the game and execute code that can do things like play the end credits or give you an insane number of items