Yowza, this was an awesome horror experience!
I'm always a big fan of these job sim games like TIS-100, Papers Please, and so on where you need to read through copious amounts of manuals of rules and lore to figure out how to pull something off correctly, and this delivered that very well! The atmosphere and vibes of the game were top-notch too: I'm not sure if I was actually under a time limit, but the tension was palpable as I hurried to figure out the steps while being assaulted on both sides from a creepy monster and an angry mob pounding on the door. So damn cool!
It's certainly a bit of an intimidating game, so much so that I feel bad since I was reluctant to wait and listen to the monster's speech (voice acting would help so much here), but I was very surprised at how friendly it could be in offering feedback when you blow it: I was expecting to have no idea how I messed it up and wouldn't blame the game in doing so, but having feedback made it an incredibly easy decision to replay, and I'm glad I did because the climatic ending sequence and the choice you need to make was awesome(ly depressing)!
If I were to have any feedback, it would be that the game can be rather unclear as to what the heck is going on, in a way that goes beyond the intended sense of confusion. For example, I thought the whole point of sealing the beast was to put him under our thrall and attack the villagers so we'd be saved, so I was a bit confused when that turned out to be the obvious 'wrong' choice. Another aspect that I'd change is to make it so that the one book which sticks out from the pack would be the main sealing ritual book, not the monster encyclopedia: the player is naturally guided towards that separate book and would help inroad them much easier into what's going on.