The basic Idea is good – even though it reminds me of Silent Hill 4 and Project Zero 3 (Fatal Frame 3 for the Most on this Forum) the basic Idea will always make for a good Base. But that makes me wonder: What is the Gameplay supposed to be like? You didn’t mention what the Player is supposed to fight (what Kind of Enemies) and how the Player is supposed to fight them. I would, as well, consider it could be some Sort of an Adventure Game without actually fighting Enemies, but you didn’t mention that among the Genre Types. And for a »Run away« Game (like Clock Tower or Haunted Ground) the Scenario would be way too small.
Most horror games that I’ve experienced pay close attention to lighting. Everything isn’t black, or really even close. It’s a combinations of darker blues, both saturated and desaturated. Use light color to determine the mood of the scene. Lighting is very very important in level design.
@ The Red Hand
I don’t do everything at one time. First I work out a concept, then I’m working on the details.
I’ve played a lot of horror games and i know what is important. (: