I have a bunch of small game ideas, and even few stories for scary games (which I've wrote myself). But I'll describe a small horror game idea:
* tile based maze dungeon
* old school graphics (with pixelization)
* 8-bit sounds (to bring the old school felling)
* tile based movement (as in old RPG games)
* simple chasing NPC with simple cut-scenes
* collection items in the maze
* simple puzzles (collection items to do something)
And here is another example, of great idea I think:
Destroy the Porn 
