a) I see a big problem in finding a good way how to hold the player in mansion. Yo do not want to lock the doors but putting outside something that would kill the player is not a solution (haunted forrest filled with strongest enemies is this case). Ideally the player should fear leaving the house even more than staying inside, but I am not sure how to acomplish this. Also - if he cannot leave the mansion, how did he get there in the first place?
b) What is the goal of the game again? The player should not leave the mansion, will spend a lot of days there (according to the idea with full moon, etc) but every day he spends there, he is less and less motivated to stay because the situation in there gets worse and worse.
c) Putting the house in complete pitch black darkness may not be that good idea. The problem is that in darkness you can not see shadows. You want neutral Nasties, bad Nasties, evil Nasties and more. It would be hard to recognize them visualy. Also dying with terrible death in pitch dark is not that punishing as killing player terribly so he can see it. And the fleshlight is not the solution here since thing that could kill you fear the light.
d) Not sure if the player would be all that scared. The exploding windows, and other effects are good but not scary. There may be shock but not fear. The Nasties coming closer and closer trying to kill you may hold the fear level high for longer time. Objects changing places could go unnoticed, rooms shifting may be only confusing. Unseen forces knocking you from the stairs - how would you present this?
e) Do you imagine linear story? It would make things like atmosphere building and preparing scary moments much much easier.
f) The other characters may be great idea but also may be very weird. If there is one or two sidekicks, you could talk to them, get closer to them ad fear for them. If you have safe room full of specialist for pick locking, hauling, mechanism constructing and ice cream licking, it looses meaning and atmosphere.
g) Would be the game scary in the day also?
Another one is sensory overload. Lots of loud noises, combined with enemies coming from all directions and a very chaotic environment overall can be scary. It may be my sensory integration dysfunction, but when I'm confronted with a sensory overload situation (Like the circus-tent-esque area in the prologue for Silent Hill 3, or the part in Dead Space where you have to turn on the engine) my usual response is to give up fighting and run, which just enhances the fear because then you're being chased, which is a primal thing that scares just about everyone.
I'm wondering, if you make this will it be 3d or 2d? 3d would probably be the best, but 2d would be easier to work with, you could have sequences where it becomes pitch black, so all you can see is the cone of the flashlight, and the rooms and hallways (Procedurally generated via premade sections similar to Nethack) shuffle when you're not looking at them. Combine this with obviously sinister sounds and you create the feel of a malevolent intelligence trying to confound you.
In 3d you can really get going with the sounds, especially if they use surround sound.
Have a common and usually not very sinister sound come from next to the player, and when they turn to see what it was have something utterly horrifying inches from their face. For extra effect, have it scream right as they look at it.
Also, no quicksaves. Quicksaves destroy pacing in non-scary games, scary games fare even worse.
... (you'd have to make it very, VERY, realistic) ...
All around are howls, cackles, and other sinister noises, and as soon as you step into the woods something starts chasing you. I don't like the idea of vanilla nasties, just superpowered. I think there should be one singularly horrifying monster that stalks you when you go into the woods, and you never get a really good look at it. It's just like Jaws, it's scary because you never see the whole shark.
After walking forward I heard a not-entirely-natural voice say "Please... Help me!". It sounded distressingly close, so I checked my immediate surroundings. Nothing, that's a good sign. Then, I see inside one of the cells a chair covered in spikes... An iron maiden, shackles... Standard dungeon affair, I suppose, but now I truly respect their ability to truly creep the fuck out of someone.
I find a lighted place where the ledge I'm standing on (in a tower, too dark to see the bottom) tapers to the right. There are some keys on the wall. Before I grab them, ding. I hear a distant ringing sound. I look around, and I see nothing. I pick up the keys, and then... DING. The bell is much closer.
But hey, pitch it to some company. I bet they'll eat it up with a spoon.
I think it goes without saying that you would need a very compelling reason for making the character, and player, want to stay in the mansion as long as possible. It may seem cliche, but there's a reason Mario is always trying to get Princess Peach back.
I think it goes without saying that you would need a very compelling reason for making the character, and player, want to stay in the mansion as long as possible. It may seem cliche, but there's a reason Mario is always trying to get Princess Peach back.
No, there isn't, not really. Mario is a stupidly submissive masochist who saves the Princess because she demands it and because he has some sort of crush on her, feelings which she never, ever returns, and she's so utterly dependent on him to get her out of trouble and she knows that he's going to, so she's sort of stopped caring when he saves her.
I don't think the player should think the flashlight is a powerful weapon. I think they should think of it as a flimsy and not-totally-reliable shield, their only barrier between them and a horrifying death.