I am fascinated by games with 2D art that still manage to give you a good scare. I guess what I find interesting is if a game can manage to translate the scares and audio design which we know from 3D environments and movies. I have never really played any though. I would love to hear some suggestions, especially with Halloween coming soon!
That's a good point. The "scary" genre spans a really wide range of games. Might help if OP lists some games that they particularly liked, and maybe any that aren't quite what they're looking for.
Consider some games that might be considered scary (not selecting these as the "scariest" or 2D, just examples of how broad a variety of scary games might be):
Gone Home. There's no killing, no monsters. But it's got a spooky ambience -- I mean, you're wandering around an house where people are missing, trying to understand what happened. I don't know if I'd call it a horror game, but there are definitely people who might call it "scary". I felt tense while playing it.
World of Horror. This has no shortage of gore, but its graphics are 1-bit and low-resolution.
White Night. That's also black-and-white, but entirely-different, derives most of the scary factor from ambience and limited visibility. No gore. You can definitely die, though.
It's pretty old now. I just was grabbing it because I remembered it and wanted an example where death wasn't an issue, not looking for recommendations.