To me a scare isn't effective if someone pops out from the other side of a room. This house feels like a tent house in that it's compact in its design, combined with being in a soundstage makes thos house feel super long. This compact design puts most of the scares within a foot or two of you which give that startle of coming out of nowhere and the unsettling nature of your personal space being violated. Also this must be staffed with some hhn veterans because a lot of them do great work with double scares and scaring off trigger. Also a lot of the actors have 2 or more boo holes so this makes it feel like there are more actors inside which gives that unrelenting feel. It all just comes together to put you on edge and provides very effective scares.
All this. I have no love for the IP, didn't remember (or maybe never saw) at least half the scenes in here, but a perfectly designed house. Tight turns, clever hiding spaces, also quick re-sets (a problem in the other houses this year). A master class in house design, any vaguely creepy IP could work in here.