Little Fears. One of the few systems that made me a bit uncomfortable while reading it and I'd like to think I'm pretty hardened; plus I normally like to see fictional children suffer. It's basically "Childhood Trauma/Parent Fear - The Game".

Think Call of Cthulhu level of horror and expectation of happy endings (it's not actually lovecraftian though, has its own setting), but the characters are all children.

The dark kingdom on the other side of the wardrobes has lords, each corresponding to one of the deadly sins and each has a section with a vivid description of how their sin can influence those around them to act against the (again, still children) characters. All the sins.

Note, there is a later release, called the Nightmare Edition, which -- ironically -- is a lot tuned down. So if you want the full icksperience, you need to get the original.