Cosmic horror, existential dread, the slow erosion of all that you are. Allowing the unnatural to kill you by inches in order to harness its power in the fight against horrors lurking just out of sight and beyond comprehension. Nightmare fuel fluff and just the right amount of crunch. Resource management, great mix-and-match character building, and a core mechanics system, the Blood & Breath System, that can easily be used for for many different genres of ttrpg.
I've been playing this game and system through its beta versions since 12/25/2017, as part of a 14 month long living campaign and as part of many short-term games and one-shots. I highly recommend it.