Samhain is an investigative horror game where players are tasked with identifying and destroying various monsters. Samhain can be played with up to four players online or over LAN.

Players can work out their target's identity by surveying their environment for various clues. Claw marks, ectoplasm, notes, corpses, and more all provide valuable information to the investigation. Once players determine which monster they're hunting, they have until midnight to gather enough supplies to destroy it. Each enemy has unique strengths, weaknesses, and behaviors that must be taken into account during the investigation. Preparing for the wrong type of enemy will result in a bloody death.