-SPOILERS-
Found a glitch. After completing the Pentagram puzzle, and checking the hidden duct, it says to be sure you've explored the house, well, in searching, I went back into the hidden space in the hall, where the key to the door was again. This reset everything past that point, so I had to get the key, unlock the door, interact with the doll, and solve the pentagram puzzle again.
Overall, excellent game. Was nice to be scared again!