Narrative sections are presented as three-dimensional animated cinematics, with camera movements and full voice acting in Japanese and English. The Escape sections, which include thirteen different rooms, involve the player searching the room for tools and clues through a point-and-click interface in a first-person perspective and solving puzzles. The puzzles are mostly self-contained, and test the player's problem-solving skills and memory; among these are puzzles where the player has to decipher messages, and ones where they have to align the sides of a three-dimensional object correctly.
After completing an Escape section, the player needs to take a stance in a moral decision; one such decision involves one character being locked into a chair with a gun next to it and another character inside an incinerator. To stop the incinerator, the player needs to choose to pull the trigger, which has a 50% possibility of firing a live bullet, killing the character in the chair. The way the decisions are made varies: some involve choosing between options, and some have the player input their own answer.
Plot
Setting and characters
Zero Time Dilemma is set between the events of Nine Hours, Nine Persons, Nine Doors and Virtue's Last Reward. The game follows nine characters who have been locked up in an underground nuclear bomb shelter and are forced to play a death game called the Decision Game, which is led by a masked person known as Zero. The shelter is divided into three wards, with three people placed in each section, making up three teams: C-Team, Q-Team, and D-Team. To get to the central elevator hall and escape, the characters need six passwords; one password is revealed each time one of them dies. The characters are all wearing watches that inject them with a drug every 90 minutes, inducing memory loss. Heavily involved in the game's lore is the many-worlds theory, where every decision made creates alternate universes where the opposite was chosen; these timelines make up the game's multiple routes.
C-Team includes Carlos, a firefighter with a strong sense of justice; Akane, a member of a secret society working for a peaceful future, and who pretends to be a "neat and clean, ideal Japanese woman"; and Junpei, a childhood friend of Akane's, who has joined a detective agency to find her after she has not been heard from. Q-Team includes a naive amnesiac boy wearing a spherical helmet; Eric, an ice cream shop clerk who easily cracks under pressure; and Mira, who does not show much emotion and is in a relationship with Eric. D-Team includes Diana, a pacifist nurse who dislikes fighting; Phi, an intelligent woman who participated in the Dcom (Dwelling for Experimental Cohabitation of Mars) experiment together with Akane and Sigma to save the world from the Radical-6 virus; and Sigma, a 67-year-old man in the body of a 22-year-old. Additionally, there is a dog named Gab who is able to pass through vents between the sections to deliver messages between the teams.
Synopsis
The nine participants of the Dcom experiment are kidnapped by a masked individual known as Zero, who makes them play a coin toss; if they win, they are set free with no memory of what happened, and if they lose they awake in a facility separated into three wards, with one team in each. After losing, they are forced to play the "Decision Game", and submit a vote for one of the teams; the one with the most votes gets executed. At this point, the story starts branching into different timelines depending on player choices.
In one timeline, Phi is killed, and Diana and Sigma are trapped in the facility. They discover a transporter device, which they use to send copies of themselves to another timeline; their original selves remain, however, and the transporter takes ten months to recharge. They begin a relationship, and Diana later gives birth to fraternal twins, a boy and a girl whom they name Delta and Phi. Using the recharged transporter, they send the babies to the past, to keep them safe from Zero. In another timeline, Akane realizes that Carlos can send his consciousness between timelines in times of danger, which she calls "Spacetime Human Internal Fluctuating Transfer", or "shifting". Through the resonance from Carlos's ability, C-Team shifts between timelines to collect passwords, but Zero sends the boy in the helmet – revealed to be a humanoid robot named Sean – to attack them for violating the rules.
Carlos flees by shifting to the timeline that the copies of Diana and Sigma had been transported to. Diana and Sigma reach a room with sleeping pods, where they find and wake up Eric and Sean, and find the dead bodies of the remaining participants. Armed with a shotgun, Eric demands to know who killed Mira; Carlos says that he must be innocent as he was in the C Ward, but Diana realizes that the wards are not separate: there is only one lounge, which changes its appearance using projection mapping. They realize that only one team is active at a time, while the rest are kept asleep in the pods. Sean reveals Zero's true identity: he is Delta, an elderly man thought to be wheelchair-bound, deaf, blind and mute, who had been with Q-Team the entire time, but off-camera from the player's perspective. He admits that he killed Mira, and prevents the participants from escaping by using his esper abilities to make Eric shoot everyone but Diana.
In the timeline leading to the events of Virtue's Last Reward, Phi is infected with Radical-6, which has a 75% possibility of causing suicidal intention. Junpei and Akane learn that Zero caused a Radical-6 outbreak in the hopes that it would kill a religious fanatic who would cause the complete extinction of humanity; Radical-6 was seen as the lesser evil, as it would allow two billion people to survive. In the timeline where no teams were executed, the participants who are able to shift recall their memories from previous timelines. Delta says that he ran the Decision Game to ensure his and Phi's birth, and to cause epigenetic changes in Diana and Sigma, giving Phi the ability to shift and Delta the ability to read minds and briefly control others' bodies.
