How about one where you play as a blind/psychic/whatever person who's only way of seeing the environment is through sound. What I mean by this is that everything is pitch black, but making noise emits light for a short amount of time. This would be an interesting mechanic to do with enemies as, you have to choose between using the darkness to evade the enemies, or using noise to find your way around, without attracting the enemy. This could also add to the scariness of enemies as you could be walking along when you make a noise to inspect the surrounding environment, when you realize that some uncanny valley-esque creature is standing right next to you, or having an enemy roar, lighting up the room and, for a short amount of time, revealing his grotesque, lovecraftian form.
I would like to see how well this idea would work, as it plays on people's fear of the dark.
I would like to see how well this idea would work, as it plays on people's fear of the dark.