The game features eleven levels, which use Zero's precognition as a framing device; the player's attempts to complete each level are presented as possible scenarios Zero has foreseen. Levels are split into several rooms, and the player must kill every enemy in a room using their sword, throwable objects, such as lamps and pots, or environmental hazards, such as lasers. Aside from occasional bosses, each enemy dies in a single hit. Certain levels feature unique game mechanics, such as a stealth mission in a nightclub, a motorcycle chase, and an alternate player character. Any damage results in instant death for Zero, requiring the player to restart from the most recent checkpoint. Katana Zero has been frequently compared to Hotline Miami (2012), as both feature levels filled with enemies, one-hit kills, and require players to determine their chosen route strategically. Outside the main game, there are two additional game modes: hard mode features more difficult levels with new enemy varieties, reworked bosses, and additional challenges; and speedrun mode challenges the player to complete every level in the fastest time possible, with the options to modify enemy behavior and skip cutscenes. Story and dialogue Katana Zero follows a neo-noir-style storyline, with psychological horror and black comedy elements, set in a dystopian metropolis after a war. Subject Zero is an amnesiac veteran with precognitive abilities. He assassinates drug dealers for his psychiatrist, who acts as his handler. The news media ascribes these killings to a serial killer known as the Dragon. Zero experiences recurring nightmares of a child, who he identifies as himself, in a hut. A scientist runs in, warns the child to hide, and is shot moments later by a soldier. He discusses his nightmares with the psychiatrist, who supplies him with a drug as treatment. Zero also befriends a young girl living next door to his apartment, and becomes attached to her. In-between levels, the player converses with non-player characters (NPCs), such as the psychiatrist, the girl, and a Russian psychopath antagonist named V, who admires Zero's lethality. In a real-time dialogue tree system, the player chooses responses during conversations and can interrupt an NPC's dialogue at any time. Their decisions determine how much exposition is presented and how Zero is characterized; for example, Zero comes across as rude if the player repeatedly interrupts. Although they do not change the overall plot, players' dialogue choices can affect certain events, and