1:48 for beginners, this is a corner kick. i don’t know how it works, but you have to jump twice there very quickly, when jumping off the wall and off the other spiked one. you don’t die from touching the spikes because spikes are programmed not to kill you if you move in the direction their tip is facing. however, you only need this tech in modded maps! and even if custom maps use these, there are way easier maps before! best of luck to whoever tries to even get to the point that you have to use it, lol.
And now, with current knowledge, we know that only 4 screens need to be modified and only 5 dashes need to be used to beat an unmodified 1b by a human! Still, super impressive for a run 4 years ago
But the question is can it be done consistently? unpredictability is unfavorable in a run, so I bet they knew that it could possibly be done, but wanted to present a fluid video but honestly that's just speculation, and idk a lot of the ins and outs of Celeste's more complicated mechanics, so I am no authority on the subject