Readable at scale. Kind of small, but readable. Good enough. I worry about the amount of open space, but absolutely baller that you have the pages showing through their opposite. I have no idea how many other people noticed that mirroring, but you are a rockstar for doing that! I almost always get a little nervous when there's so much open space in an entry. Cover dedicates almost exclusively to the bare minimum. Title, Interesting visual, who made it, what system, jam info. Back cover is a quick blurb to set the tone, followed by a basic bit of information on what someone can expect from playing this. Nice choice to add a link there as well as the note of 'review copy' since this is being offered at a price outside of the jam.
Clean and professional so far. No complaints. You've managed to hit theme, writing, and some of visuals already quite well. Into the game itself. Card explanation is pretty strait forward. No idea how many people automatically know what a desire path is, but it isn't a wrong choice per se.
Kings to you Fernand. You did something that no one else has yet. You shut me up. I normally pick out bits and comment as I go. I'd already read all the way to the villager stats before realizing I hadn't said anything. Whatever else happens, know you gained that victory. There's a lot of ways this might not work well. This is a setup I would only use if I don't have a contrarian player in the group. Still, assuming everyone is willing to stick around in the village, it's solid.
The horror itself is a thing that never quite reveals itself. It isn't incredibly powerful and instead uses the fog to succeed. The little bit about feeding itself to the young is interesting. Odd little point, but implies it exists beyond the scope of this game. That's always nice. The fact it never changes forms also means that even killing it, they aren't really sure if they killed the right person until the dying stops. After a few deaths, I could easily see villager families starting to proactively attack one another as well, making it even harder to know who the real horror is.
My biggest issue is that this is almost entirely setting and very little substance. If that makes sense. We know what's going on and have mechanics for it, but we know basically nothing about anyone here or their lives and the GM is going to be making a LOT of things up on the fly to manage a viable murder mystery. There's a note about the horror being able to lie and shift blame, but all of that is on me if I want to run this. The single biggest element of a mystery is the mystery itself. The red herrings and the hidden clues. We have a what, a why, and even a how technically. What we lack here is the part of a mystery that makes it really fun for people. That trail of hints that lets them feel like a genius if they figure it out or like it was so obvious they don't understand how they missed it when they get it wrong.
Looking over the names, it's cute that you tied the suits into their surnames. Nice touch. I did find it odd that for a place all about refusing to believe in the supernatural, one of them believes in werewolves and another is interested in witchcraft. Found that a little jarring. I presume the point of them disbelieving in the supernatural is so they can't be convinced of the horror's existence instead of their own selves as the cause. It more or less says so in the text. Having two of them believing/interested in the supernatural is a very odd choice.
Under the seers section, I would honestly be happier to just have it's face look empty when it is preparing to attack. That way I am not making an artificial effect on play just to keep the mystery. Instead, I have a setting-specific element that creates uncertainty. This could be really interesting if it took a bit of damage and escaped. Then it might sneak off and harm someone else in the same way so that in the morning the players checking others would find the wrong person! Some fun to be had there. Honestly, with 4 HP, it's probably not making it out alive either way though. I'd personally also be inclined to have its HP go up after every kill so that the longer it goes on, the harder they need to work to end it's reign of terror.
One thing I was thinking was that you had us pull 2 cards from the pile at the start to represent murders, then pick another of our choice to count as the murderer. To me, it feels smarter to have the GM pull 2 cards. The first is who was murdered, the second is the Horror's disguise. Then everything gets played strait and I am entirely random each time I run this with no way for players to sus out how I think in a way to get a hint ahead of time on who the horror is. Good GMs aren't going to be easily caught out, but newer GMs might find it trickier.
As a whole, this is good. I think it can gain a lot from expanding to create a way to readily set up clues. Making such a system is probably tricky since you don't know in advance who did what, but if you focus on things relating to the non-horror villagers as they grow ever more panicked, you can mask the horror itself through the increasingly desperate actions of the villagers themselves. Anyway, I like it. A lot in fact. Good job.