Day 28 - Scariest Game You've Ever Played
I've played some nail-biting D&D games and tension filled cinematic unisystem, but the only game I've truly had fear playing was Call of Cthulhu.
I used to game with a group that played periodic CoC. We would do one shots using the same characters (if they survived). One of the things that made these games scary was the atmosphere involved. We always played at night and typically played by candle and oil lamplight. Sometimes creepy music or sound effects were involved. The atmosphere and mood is what made the games so scary.