This is an adventure platformer in which players assume the role of Mono, a boy trying to survive a strange, hostile world. As players traverse mysterious environments, they can run, jump, climb, and sneak around various obstacles and enemies. Getting caught by the large ghoul-like enemies usually results in Mono's death: getting struck by objects; being chased and shot; getting eaten alive. The game often has a dark tone, with sounds of characters screaming, depictions of body bags and meat grinders, and blood stains splattered on objects in a hospital and morgue. One sequence depicts human-like characters falling from rooftops, apparently committing suicide.