When you go about constructing a horrifying environment there's a few key things you need to build up before you'll actually get anywhere. I've played around with some survival-horror concepts inspired by Amnesia and Penumbra and here's what I personally think makes a horror game well made:
ImmersionIn order for the player to actual feel any fear they have to be able to place themselves in the subject's shoes. You could nail every single aspect of the emotion of fear but so long as the subject knows they're safe behind their screen, they're never going to feel scared. Immersing the player isn't a very easy task but it's the most essential. Some ways you can make the player feel immersed is by allowing them to interact with the environment in a large amount of ways. Let them be able to explore, investigate, touch, move, push, throw, feel, observe. Build an environment that is dynamic and fluid, something that breathes, something that changes. Obvious patterns will break immersion, as well as any glitches or bugs, and out-of-place things like changes of style, weird colors, out of place sounds, ect.
AtmosphereOnce you have immersed the player, you have total control over their emotions. Now we can begin to adjust their emotions or sway them based on what the subject sees and feels. We could put them in a bright sunny field and make them feel happy, we could put them on a rollercoaster and give them an adrenaline spike, we could put them in a mountain range and make them feel cold. In this case, we want to make them feel un-safe. Build an environment that seems hostile. Don't fill it with enemies at every turn, make them feel alone. Eerie gusts of wind and audible silence brings a great unease that'll keep a player on his toes. Take special care of color, music, ambiance, and make sure it all seams together.
Character DevelopmentIf the player couldn't give a stuff about the character or his story, why would they care if they lived or died? By building a human, deep, interesting character, the player will be more adverse to watching them suffer and therefore will feel more fear from imposing threats.
PsychologyThe brain interprets things in different ways. You cannot build fear if you do not understand what fear is. There are a massive array of tools you can use to trigger certain thoughts or subconscious feelings in a player. Small motifs, symbols, details, all these things need a great deal of attention and care when building a scary environment. Color, sound, all these kinds of things. Some things you may play around with are common sources of fear, such as
- Fear of the unknown (darkness, unreachable areas, sounds you can hear but cannot find the source of)
- Fear of what we don't understand (higher consciousness, monstrosities, anomalies)
- Fear of isolation (loneliness, solitary)
- Fear of death (this is p obvious)
Here's an example of a horror build I tried to create a while ago before I lost the save (it was far from finished):
https://www.youtube.com/watch?v=95WgOxO8qbk