I think a big issue is that the visual look of the Rotting Stone just ... isn't that scary? You can see it's effects everywhere, there are bits of porous stone across walls and pillars and taking over people, but it never really comes together for me. The stone isn't inherently freaky looking, so it needs context to make it scary. Unfortunately, there is never a moment where the concept clicks, and it's kinda all over the place because of it. There's a Mask Guy that is a black jumpsuit wearing an ancient mask? There's a Viking that mostly just looks like a regular Viking? There's victims being taken over by the porous stone stuff? Some of them are taking their own heads off... I think? It's really scattershot and it doesn't mesh as a whole.
In some ways, I appreciate them taking a bit of a risk with the concept and going a little bit crazier than just "The exhibits are alive!", but I also kinda wish that's just what we got instead. The Rotting Stone is unique to this, but it's also not portrayed very well at all. I think if it was a little more body horror-y, if the exhibits they chose to possess were easier to read at a glance as "Cowboys, Mummys, Dinosaurs, Taxidermy Animals", I think it would sell a lot easier.