Honnestly without a savestate for the level up shift, even if its *only* 20min run, you would need a freaking practice to be able to pull it "live", i would realy be impress
Tough i would not say impossible, outofthegamer did pulled a ~27% score with 3 save rooms in console, and that was realy not easy to perform, so i believe that speedrun can be "mastered", but youll get lot of failure for sure lol
For some very particular situation, i have flawless method for level up shift, i mean like working every time with easy timing and same way, one for exemple is the poison plant in the library
I would need to make a small video (anyway outta need it...) showing this one, it work always the same way, pretty easy to learn the timing
But for the guardian problem is that he have heavy hp, and on video its cut, but you can believe me yuntian had hard time to bring back the green guy and doing level up like that, this probably made him lost a lot of time (not even speaking of the fact any wrong hit would be lethal)