This is a TAS (tool assisted speedrun); in other words, hacks. Under the hood, there were pauses and checkpoints used to create this run. It's meant to demonstrate what the perfect run would look like, and for entertainment.
Full TAS playlist: https://www.youtube.com/playlist?list=PLaphiC09M5gbrOku24MZGbdyMtUKWqRdL
First TAS for the agility update! This TAS obsoletes the previous one (0:56.818) despite this one being slower due to shortcut patches. I actually had already completed one using these new shortcuts, but couldn't upload it because the agility update was released between recording and uploading them. (If you want to see that, here it is: https://www.youtube.com/watch?v=q1B078iO6EE ) Also, I've started putting a little more effort into my thumbnails!
The climb onto the torch is done in one jump by also climbing on the arrow below it. The headhitter jump is actually pretty difficult to pull off, but if done like this, it can save a couple seconds. The backjump on the door is only possible in low detail mode, hence why this is recorded in low detail mode. It's still really difficult to pull off anyway, and saves about a second or so. In the swimming section, although it's hard to see since swimming is done in first person (and smarty me decided to face directly down), the TAS swims into the floor, giving it a little speed boost.
Completed: Apr. 3, 2021