Cthulhu Dark is a tabletop roleplaying game of cosmic horror, in the style of H.P. Lovecraft.
Rules light, like roll a six sider, that is how well you did, a six gives you a glimpse of that which ought not be known, are the rules.
It's about the things we fear, amplified until they are unbearable. It's about stories that genuinely creep you out, not well-worn tropes and creatures you've seen hundreds of times before.
And it's about bleak horror, in which humans are powerless when confronted by hyperintelligent alien horrors. You can't beat them. You can't fight them. You can only watch, run, hide and fear.
If you love Cthulhu games already, then this is Lovecraftian horror at its most intense. If you're new to them, then Cthulhu Dark is a great place to start. You'll enter a world of stories that are both terrifying and terribly human.
The rules are incredibly short: they're tightly focussed on horror and they drive the game.