Thanks for the submission! I didn't find any real issues with it so its totally good for the bundle, but since I looked through it I may as well list some minor potential flaws.
I think if I were to find something to complain about, it would be that there could be a bit more of what the system is intended for in the document itself, the info on the itch page is good, but some of that in the document or a tiny bit more description of what you mean by a three act structure or whether sanity should have an effect before complete break down would be nice. But I can see how there is value in leaving things as open as possible.
Also the 3d20 method of derived stats may be a bit too swingy and being able to set a stat to auto succeed (especially in a horror based system) might be a bit overly generous... but instant death on failure in act 3 mitigates and thats all sort of subjective.
I also took a look at spooky cats, and I really like that you made a more cozy low stakes variant, and that the tone is described in detail.