Ohohoho! I've got an idea that may just end up working rather well....
Under some unknown circumstance in Medieval Europe, everything has suddenly become a whole lot more real: Vampires have begun to prowl the night (These are REAL classical vampires: aka. Sunlight doesn't kill them, it just means they can't use their full abilities and can blend in more), Werewolves, due to a constant full moon every night, are out in force. And worst of all, there are reports of zombies in some area's. Nobody knows why or how these things happened all they know is they are happening.
In this game you play a boy squire who was conscripted into a war between lords who is at this moment the only survivor of a small band of knights that were sent to investigate. Just a sword and the clothes you wear on your person, you have a choice: Trek ALL the way back to your kingdom (It's a LONG trip by the way), which by this point is afflicted with the same curse, or find a way to nullify the threat once and for all.
Doesn't sound scary? Ok, let me try this: The game runs on a day and night cycle. By day, you are free from supernatural threats (Barring zombies) and have to instead worry about bandits and other human threats. Your only safe haven is towns and some cities in the area, but they aren't full-proof. Once night hits though, BAM! In this game you are on your own, you won't get any allies aside from a few merchants in the towns..but that's it.
Still not scary? Alright, let's add in the Dark souls style of combat and level of difficulty. After all, you're main character is an untrained boy squire up against unholy abominations...who predominantly travel in groups. Your character will also have a 'tired' gauge. This doesn't do too much but, if your character doesn't get enough Z's some of his attributes get effected: He won't be as accurate with weapons, he won't be as quick to react or move as if he wasn't tired. Oh! And, let's not forget, he won't be able to pick up on threats as well. There isn't a radar or any real hud aside from weapon durability (Oh yeah, didn't think i'd leave that out didya?), your health and the tired meter.
Not quite scary enough yet? Not even after the day/night cycle, the dark souls level difficulty and combat, the fact your playing as an untrained boy? OK! Then how about this. Remember how i said before about the safe-havens being full proof? Well, sometimes, no matter where you are, there is a chance you may just be attacked. For example, say your character decided to rest at an inn. But, in the middle of the night, he's awoken to find a vampire in the center of the room who's managed to charm the entire inn into being asleep to drain them of blood. Cue chase from a creature whose faster, more powerful, and has access to magic while your stuck with limited supplies. Another Example, your character decides to sneak in and stay with a small peasant family for the evening. Half way through the night, WAM! Door gets caved in by a werewolf..and it's out for blood. Have fun.
So yeah: medieval time period weaponry and equipment combined with supernatural threat with a weak as hell lead character who, while able to fight, isn't built for it at all against monsters that are DAMNED hard and practically no safe havens with higher chance of danger anywhere provided it's night. Tell me that doesn't sound at-least slightly scary?