So this is actually my third attempt at running the game, and the first attempt that end up finishing the game. You can clearly see how much I poorly played (+my game stopped responding two times, you can see it when the loading screens are way too long.. :/) as I did many mistakes during the run. And I don't know why but the Guards Cultists when entering the Mansion (before you get your first mask) were not where they should have been, I don't know why this happens, on my two other attemps I can run straight foward without caring for them because they are all already set up in the good position so I don't get detected. So I had to wait for the guard to move, then you also see that I don't know exactly how to do the doors puzzles (where you spin the parts to open the door) and, again, lost a considerable amount of time here.

I think that if I ever run this game sub 30' is way doable.