Zettai Zetsumei Toshi 3: Kowareyuku Machi to Kanojo no Uta takes place in 2012 on a man-made island in Japan, where the main goal is to reach the mainland safely in three days while the city is slowly devoured by the sea. The game follows the tradition of its predecessors focusing on defensive survival mechanics and a linear storyline.
The player chooses one of two protagonists, Rina Makimura or Naoki Kousaka, an 18-year-old and a 19-year-old respectively, who came to the Central Island City to start their studies at the university. The game starts when the character is on the bus hit by an earthquake, and then escapes the tunnel. Along the way, Saki Honjou and Ayami Hazuki join as fellow survivors, encountering mysterious gunmen, and dealing with a theme of greedy corporations ignoring safety warnings in favor of profits.
The gameplay involves controlling the character directly, navigating both indoor and outdoor environments, while dealing with difficult situations such as smoke inhalation, floods, and earthquake tremors. Survival mechanics include item crafting to create tools and inventory management. The game also features story sequences when new characters are encountered or require support or rescue.
The player's choices can influence the storyline and different endings, but there is no morality system that constantly shapes the character. Instead, the stress meter (ST bar) influences the protagonist's health (HP bar), with factors such as exposure to danger and sights like corpses affecting the stress level. The player must maintain the stress meter by sitting down on a bench, drinking water, or using a medikit.
Character customization is also available through clothing options, and local ad hoc multiplayer supports up to four players in separate cooperative missions.
