Time by time, night by night the game doesn’t hit you or pressure you with different scares, just the same way all the time. You begin to know of what you gonna expect from when you face against Rake again, so it won’t hit you with a scare like from the start of your game experience anymore.
Same case with Phasmophobia, you get “immune” from scares.
My idea for a horror game is fairly graphic and bloody and should be taken with a grain of salt.
But, if you really want an interesting game:
Modern day Robloxia, news goes around: people are going missing, with sightings of a strange creature taking them away.
You decide to investigate, out of VERY stupid curiosity. You see blood trails and what appears to be limbs, a very strange sight. You end up being chased by the monster, and you somehow narrowly escape in some building.
You realize, when you flick on the lights, that this is a torture chamber. Dead bodies, blood, gore, the whole shabang.
The creature that was chasing you earlier is somehow behind you now, despite the door being locked. You don’t notice, as you are mystified and in terror at the sight of all these inhumane instruments of torture and what they have done to their victims. You get jumpscared, and the camera goes black. “The End?”
Horror games are really not scary anymore, but this might give people chills.
Make the enemy unclear and anonymous. Make it unpredictable. Never let the player know its full capabilities. This can be done by requiring the player to hide in a wardrobe or under a bed for example and only allow them to see little glimpses of the creature, which makes it more terrifying.