Does anyone know how I can skip the cutscene that appears in the first video

I've noticed that leiteset has managed to do this, but I'm not exactly sure how to do this  (sorry my bad english)

https://m.youtube.com/watch?v=0EDPIFvv_jw

https://m.youtube.com/watch?v=VRXoAtJAvOQ

which version is best for speedruns? I've heard that v1 is not very good for this.

what is this and how these runs can be so much faster than any%