Katana Zero is a 2019 platform game created by the indie developer Justin Stander. Set in a dystopian metropolis, the neo-noir storyline follows Subject Zero, a katana-wielding assassin with amnesia who can slow down time and predict the future. Zero unravels his past while completing assassination contracts. Katana Zero features side-scrolling hack-and-slash gameplay in which the player attempts to kill all enemies in a level without being hit, using Zero's abilities to manipulate time, dodge attacks, and take advantage of environmental hazards. In-between levels, the story is told in sequences where the player converses with non-player characters through dialogue trees. Stander began working on Katana Zero in 2013. He had previously developed freeware games, such as Tower of Heaven (2009), and conceived Katana Zero as his first commercial game. Using GameMaker Studio 2, Stander sought to make a difficult story-driven game that did not force the player to wait through dialogue and cutscenes. He focused on attention to detail and looked to films such as Sin City (2005) and John Wick (2014) for story inspiration. The development was prolonged and Stander worked mostly alone, although he recruited artists to design the visuals as well as musicians Bill Kiley and Thijs "LudoWic" Lodewijk to compose the synthwave soundtrack. Katana Zero was published by Devolver Digital for macOS, Nintendo Switch, and Windows on April 18, 2019. It sold 500,000 copies in less than a year and received positive reviews. Critics praised the gameplay—which they favorably compared to Devolver's Hotline Miami (2012)—and the visuals, writing, and music. The story divided reviewers, while the unresolved ending was criticized. Several critics cited Katana Zero as one of the best games of 2019 and it was nominated for numerous year-end accolades. Ports for Xbox One and Amazon Luna were released in 2020 and 2021, downloadable content is in development, and Stander intends to continue the fictional universe in future games. Gameplay Katana Zero is a 2D platform and hack-and-slash game presented from a side-scrolling perspective. Controlling the player character, the katana-wielding assassin Subject Zero, the single player completes assassination contracts for a psychiatrist. Zero can run, jump, wall kick, pick up and throw items, attack using his katana, and dodge. Zero's ability to slow down time and predict the future allows the player to activate a slow motion effect, enabling them to predict enemy movement easier, although use is limited by a meter that gradually refills.