Wander around liminal spaces with a camera, taking photos before moving onto a new area. There's a constant, subtle creepy atmosphere, but you're never in any real danger, except in the secret alien level where you shoot 65 cryptids to death.

As is often the case with exploration based games, what you get out of the game's environments will decide if you like this game or not. Personally, I enjoyed Hypnagogia 無限の夢 Boundless Dreams more, a game by the same developer.