You’ve talked about how to design a horror game but it doesn’t seem like you like horror games. How would you design a horror game that YOU would play as in, what the gameplay be like (actiony, stealth, puzzle, etc.)
I’d aim for somewhere between action and stealth. A lot of horror games use puzzles as filler between the horror bits, but they don’t put a lot of effort into the puzzles, and I don’t think puzzle solving meshes well with horror. You essentially need an excuse to wander a large area, and puzzles can be used to that end by ferrying pieces back and forth, but that means people can’t see the whole puzzle at once, and it delays a lot of the feedback of getting stuff right or wrong which by itself would be irritating, and it gets compounded by the spook factor, so I don’t think it’s totally the best idea.
The trouble with horror is that you need a lot of not-horror to make it work, or people condition themselves and become desensitized.
Maybe the Queen Vanessa levels from A Hat In Time might be a good angle to work from.
Basically you’re set up with a bunch of essentially chores to do, then it makes a loud noise and HOLYSHITOHGODGETAWAYFROMME. You could get the enemy to come in on cycles, patrol around, you have hints it’s getting near, so you gotta hurry up while you have time. Then something that increases your risk factor, or something that requires you to take certain risks, something that alters the enemy’s scheduling a little to shake things up. Imagine that when the enemy is directly in your room, you can’t just hide the whole time, you NEED to move because it will eventually check your hiding spot. So imagine it’s like playing Perfection combined with Operation (the board games), you have this time limit you’re working against but you’re also really tense from trying to not screw up.
Couple that with a bit more potentially risky but seemingly empty traversal, a bit more randomness, a few more enemy types that have different behaviors, sections where you can’t always perceive the enemy, or know whether there is an enemy or not, and it could work.