Abyss深淵 is a first-person narrative game developed by Nightmore Works. The game is set in a future world where a giant abyss appears, and a strange substance called the Dark String appears, changing the world. Players take on the role of Red, a member of the SCR Special Forces, who is sent to investigate abnormal events at an abandoned facility in the mountains. Red is the only person in the world who can control the Dark Strings, and she is always accompanied by a bunch of strange creatures called LinkZi. The game is primarily a first-person walking simulator with exploration and dialogue mechanics, where players experience simple puzzle-solving levels while watching the plot and uncovering hidden secrets. Abyss深淵 is a unique adventure game that uses the Dark Strings to connect two related things, swing and move at a specific fixed point, spy on other worlds, and investigate the storyline by talking to NPCs and exploring the abandoned facility.