Katana Zero is a 2019 platform game developed by American indie studio Askiisoft and published by Devolver Digital. The game is set in a dystopian city, and its story follows Subject Zero, an assassin who uses a katana and has amnesia. Zero can slow down time and predict the future. As he completes assassination missions, he learns about his past. The game uses side-scrolling gameplay where players fight enemies without getting hit. Players use Zero’s abilities to avoid attacks, control time, and use environmental dangers. Between levels, the story is told through conversations with characters using dialogue choices.

Katana Zero was created by video game designer Justin Stander, who started working on it in 2013. Before this, he made free games under his studio Askiisoft, such as Tower of Heaven (2009). Katana Zero was his first paid game. Stander used GameMaker Studio 2 to develop the game. He wanted to create a challenging story-driven game that did not require players to wait through long dialogue or cutscenes. He focused on details and took inspiration from movies like Sin City (2005) and John Wick (2014). Development took a long time, and Stander worked mostly alone. He hired artists to design the visuals and musicians Bill Kiley and Thijs "LudoWic" Lodewijk to create the synthwave soundtrack.

Katana Zero was released for macOS, Nintendo Switch, and Windows on April 18, 2019. It sold 500,000 copies in less than a year and received mostly positive reviews. Critics praised the gameplay, which they compared to Devolver’s Hotline Miami (2012), and the visuals, writing, and music. However, some reviewers were divided about the story, and the ending was criticized for being unclear. Many critics called Katana Zero one of the best independent games of 2019, and it was nominated for several awards.

Later versions of the game were released for Xbox One in 2020 and for Android and iOS through Netflix Games in 2024. Additional content is being developed, and Stander plans to continue the story in future games.

Gameplay

Katana Zero is a 2D platform and hack and slash game played from a side-scrolling view. The player controls Subject Zero, an assassin who uses a katana to complete assassination jobs for a psychiatrist. Zero can run, jump, kick off walls, pick up and throw items, attack with his katana, and dodge. Zero has the ability to slow down time and see the future, which lets the player use a slow motion effect to predict enemy movements. However, this ability is limited by a meter that slowly refills. The game includes eleven levels, each framed as a possible future scenario that Zero has foreseen.

Each level is divided into rooms, and the player must kill all enemies in a room using their sword, throwable objects like lamps and pots, or environmental dangers like lasers. Most enemies die in one hit, though some levels have unique mechanics, such as a stealth mission in a nightclub, a motorcycle chase, or a different player character. If Zero takes any damage, he dies instantly, and the player must restart from the most recent checkpoint. The game is often compared to Hotline Miami (2012) because both games include levels with many enemies, one-hit kills, and require strategic route choices.

Outside the main game, two additional modes are available: hard mode has more challenging levels with new enemies, redesigned bosses, and extra challenges; speedrun mode challenges players to complete all levels in the shortest time, with options to change enemy behavior and skip cutscenes.

Katana Zero’s story follows a neo-noir style, blending psychological horror and dark humor, set in a dystopian city after a war. Subject Zero is a veteran who has lost his memory and has the ability to see the future. He performs assassinations for his psychiatrist, who acts as his handler. The media blames these killings on a serial killer called the Dragon. Zero has recurring nightmares of a child, who he believes is himself, in a hut. A scientist warns the child to hide and is later shot by a soldier. Zero shares these dreams with his psychiatrist, who gives him medicine to help. Zero also befriends a young girl who lives near his apartment.

Between levels, the player interacts with non-player characters (NPCs), such as the psychiatrist, the girl, and a Russian antagonist named V, who admires Zero’s skills. A real-time dialogue system lets the player choose responses during conversations and interrupt NPCs at any time. These choices affect how much story is revealed and how Zero is portrayed, but they do not change the main plot. For example, if the player interrupts often, Zero may seem rude. Some events and a boss fight can only be triggered by making specific choices.

As the game progresses, Zero and the psychiatrist’s relationship becomes tense because the psychiatrist becomes more disagreeable, and Zero suspects he is hiding information. Later, another swordsman with precognitive abilities, who claims to be the real "Dragon," captures V. Zero learns he was once a supersoldier called a "NULL" and that the drug Chronos gave him his abilities. However, the drug causes users to become trapped in their own minds during withdrawal. Zero is tasked with killing the Dragon but fails after facing a marksman named Headhunter. He is forced to kill police officers, but when cornered, he is confronted by two men in drama masks who offer him a choice: live with an unknown cost or die permanently, which leads to an alternate ending. Zero later destroys a bunker with secrets about Chronos and kills Headhunter. He spares the family inside the bunker and, tired of being controlled, kills the psychiatrist. The girl disappears, likely kidnapped by the masked men, and the story ends with a cliffhanger. A flashback reveals Zero’s nightmare is a memory from the war, showing him as the soldier who shot the scientist and working with the Dragon, who was named Fifteen.

Development

Katana Zero was created over six years by Justin Stander, an independent game developer who used the studio name Askiisoft. This was Stander's first commercial game. Before this, he made smaller free games, such as Tower of Heaven (2009). After seeing the success of Terry Cavanagh's game VVVVVV (2010), Stander realized that people only pay attention to indie games if they are sold. Cavanagh, like Stander, had started with free games, but none were as successful as VVVVVV. Stander wanted to create a bigger project that could be sold and tell a story. He began working on Katana Zero in 2013 as a hobby during his second year of college at McGill University. He used the GameMaker Studio 2 game engine and spent the first two years making simple prototypes. The game was a way for Stander to express himself outside of schoolwork, and he spent most of his time at college developing it.

After graduating in 2015, Stander worked on Katana Zero full time. He also worked on other projects at the same time because he believed the chances of success were small. The total budget for the game was US$60,000, which Stander said was very small for a game of this size. He explained that he did not pay himself and cut costs in his own life to focus on the game. Stander mostly worked alone, but he hired help for the art and music. The game was first made for computers (macOS and Windows). Stander decided to make a version for the Nintendo Switch right after the console was released because he believed it was a good platform for indie games. GameMaker made it easy to move the game to the Switch, and the long development time meant the game was already well optimized.

One of Stander's goals was to make killing in the game feel exciting and satisfying. He thought many modern games were too easy, with enemies weaker than the player. He found it hard to die in games like Payday: The Heist (2011), so he made Katana Zero difficult but fair. Players would need to take responsibility for their mistakes. He continued a design style from his earlier games, such as Tower of Heaven and Pause Ahead (2013), which used short levels with instant-death scenarios. The one-hit-kill gameplay was often compared to another game, Hotline Miami. Stander said he only played Hotline Miami once and did not remember its gameplay, but he admitted it might have influenced him. He named Samurai Gunn (2013) as the bigger influence, as he felt it used one-hit kills effectively.

Stander wanted Katana Zero to feel like a movie and to change what players expected. He said, "As soon as you think you understand how the game will play, I try to completely change it. I do this many times throughout the game." To keep the experience varied, he included many types of enemies, environmental traps, alternate paths, and special level designs. A minecart pathway inspired by the movie Indiana Jones and the Temple of Doom (1984) took over a month to create. Stander looked to other indie games with fast, intense combat for ideas, such as Trilby: The Art of Theft (2009) and Gunpoint (2013).

The art style was inspired by the bright, neon lighting of the 1980s. Finding artists was difficult for Stander, who called himself "a terrible artist." For two years, no artists worked on the game. He found help through an online community called TIGSource, but it was hard to find high-quality pixel artists who would commit to the project. Many artists only worked for a short time before leaving for other reasons. Stander used the neon lighting to blend the different artists' styles. He said getting an artist team to finish the game was a matter of luck and credited the artists with helping him complete it.

Stander focused on small details, saying that adding a single feature, like a gun turret, required changing many systems, such as lighting, to keep everything consistent. He wanted the game to feel perfect, with no bugs. He said, "Everything needs to feel like an extension of the player. When you play it, you should always feel like this is exactly what I wanted to do." When making small free games, he could spend a year on a short 20–30 minute game. Applying this careful approach to a full-length commercial game made the development take longer than expected. Stander originally thought the game would take one or two years to make. His focus on details sometimes made him feel discouraged, and he made little progress for a year.

Stander said telling a story was a big reason he made Katana Zero. He wanted to celebrate his favorite movie themes and add his own ideas. The script was written by Stander and Eric Shumaker, with help from Sterling Nathaniel Brown and Ian Goldsmith Rooney. Stander worked on the game one element at a time, so he only had a basic plot summary when he finished designing all the levels. Early ideas included a main character who was "trapped in their situation" and a disliked psychiatrist.

Katana Zero is a mix of movies Stander enjoyed. He was inspired by samurai films and wanted a main character who was both vulnerable and deadly, like those in Korean revenge movies. Films that influenced him include Oldboy (2003), Sin City (2005), Drive (2011), and John Wick, for their "invincible-yet-human" characters and "stylistic violence" in dark, neon-lit settings. He also drew from Seven Samurai (1954) and the movies of Quentin Tarantino. The story was inspired by Hotline Miami, which uses mysterious phone calls to direct the player to kill. Themes include drug addiction and mental health. Stander hesitated to include these topics because they had never affected him, but after research, he felt he could handle them respectfully. He rewrote the script about 30 times.

Stander allowed players to interrupt any spoken dialogue because many action games he played "would stop to let characters argue or deliver long speeches." He thought this was a problem because it took control away from players. He also believed an assassin like Zero would not wait to listen to villains explain their plans. He added in-game consequences for interrupting dialogue to make the experience feel real. He used a "show-don't-tell" approach, trying to tell the story, themes, and character traits through visuals instead of words. A level where the player controls a character named Dragon was meant to show the character's power without using dialogue.

The dialogue system in Katana Zero came from Stander's idea for a role-playing game (RPG) where players could interact with anything and fight anyone. He wanted every action to have consequences, similar to games like Grand Theft Auto. Though he never made the RPG, he used the dialogue system in Katana Zero to keep the game's pace consistent. Finding the right timing between interrupting and responding was difficult. Playtesters sometimes chose the wrong response if they interrupted the dialogue.

Release

Katana Zero was first shown to the public at PAX West in Seattle in September 2015. Adult Swim Games got the rights to publish the game, and a short video was shared in December. The game was planned to come out in late 2016, but it was delayed to 2017 and then to March 2019. In December 2018, the game’s creator, Stander, said he had "ended his partnership peacefully" with Adult Swim. The next month, Devolver Digital got the publication rights. Devolver helped Stander translate the game into ten languages. Stander was impressed by Devolver’s testing process, which found problems he had not noticed.

Katana Zero was released on April 18, 2019, as a downloadable game on GOG.com, Humble Bundle, Nintendo eShop, and Steam. The Switch version was temporarily banned in Australia after the International Age Rating Coalition refused to classify it because of its graphic violence and drug use. Devolver Digital resubmitted the game to the Australian Classification Board, which approved it for release in May with an R18+ rating, meaning only adults could purchase it.

A physical version of Katana Zero for Nintendo Switch was announced in July 2020, with pre-orders planned for November of that year. As of January 2026, this version has not been released.

Katana Zero was Devolver’s most-preordered Switch game. It sold over 100,000 copies within a week of release and became Devolver’s second-fastest-selling Switch game, after Enter the Gungeon (2017). It was the second-bestselling eShop game in the month following its release, after the Switch version of Cuphead (2017), which came out on the same day. Katana Zero sold 500,000 copies in less than a year and earned US$5 million in revenue. In comparison, the average indie game earns about US$16,000. Stander said Katana Zero was most successful on Switch and Steam. Sales were strongest on Switch at first, but the Steam version sold more over time because it was often available for purchase.

Reception

Katana Zero received "generally favorable reviews" from Metacritic and a "Mighty" approval rating from OpenCritic. Critics described the game as stylish and well-designed. IGN said it improved the one-hit-kill gameplay formula in a way that felt fresh and exciting. Nintendo Life and Nintendo World Report called it a standout title in the Nintendo eShop. Destructoid’s reviewer described the game as "bleak, beautiful, bloody, and brilliant" and said it changed how he viewed video games.

Reviewers praised the 16-bit visuals and retro VHS aesthetic. They appreciated the detailed sprites and animations, though some noted the intensity of the visual effects could cause headaches. IGN highlighted impressive lighting effects that worked well with the neon style and sprite art. GameSpot and Polygon said the retro look was not used just for nostalgia, and the detailed animations added emotional weight.

The soundtrack was widely praised. Destructoid called it an "audial delight," and Nintendo Life said the music sometimes overshadowed other parts of the game. Reviewers noted the soundtrack had a clear focus and included original compositions that avoided common chiptune styles. IGN and PC Gamer said the music was well-suited to the game’s world.

Critics had mixed opinions about the story. Destructoid said it was hard to discuss because much of it relied on player interpretation. Shacknews praised the plot twists, and GameSpot said the story balanced graphic violence with quiet character moments. Some reviewers appreciated how the story explained the slow-motion mechanic, while others found the plot generic or unfulfilling. PC Gamer and Game Informer said the ending felt abrupt and that some story moments lacked resolution.

The dialogue system was described as creative and innovative. Reviewers said branching dialogue paths and alternate story scenarios increased replay value. The visual effects used during conversations were praised for adding emotional depth. Destructoid and Nintendo Life said the system made the story more engaging, while Polygon noted it helped players connect with the main character. IGN noted some story choices felt shallow but still called the system entertaining.

Reviewers praised the fast, fluid gameplay, often comparing it to Hotline Miami. IGN said the controls were flexible and easy to learn, and Nintendo Life said the gameplay felt satisfying. Many compared the game to a puzzle, saying players had to plan and strategize to complete levels. Game Informer said the trial-and-error process of refining movements was the most enjoyable part. However, Polygon felt the gameplay did not match the game’s strong presentation, and some said the short length was a drawback.

Critics noted the player character’s abilities were limited and did not change throughout the game. Game Informer said this was a problem, but USgamer and PC Gamer said the limited abilities still allowed for varied combat. GameSpot, Destructoid, and IGN said the variety of enemies and set pieces kept the gameplay interesting. IGN highlighted the Chronos slow-motion mechanic as a favorite feature, and Nintendo Life said balancing its use was exciting. Destructoid praised how enemies did not reset to their original positions after dying, though Game Informer found this annoying.

Katana Zero was among the top 50 highest-rated games on Metacritic in 2019 and was named one of the best games of 2019 by USgamer (#1), Thrillist (#21), and Red Bull. IGN nominated it for "Best Action Game" and "Best Video Game Music/Soundtrack" in its Best of 2019 Awards. The game’s lead designer, Stander, was included in Forbes’ 2020 30 Under 30 list.

Post-release

Devolver released an Xbox One version of Katana Zero on October 15, 2020, available to Xbox Game Pass members. An Amazon Luna version was released on December 9, 2021. A PlayStation 4 version was reviewed by the Entertainment Software Rating Board in March 2021, but it has not been released as of September 2022.

Android and iOS versions of the game were released on May 21, 2024. These versions were published by Netflix as part of its growth into video games. While the apps are free to download, they require an active Netflix subscription to play. Reviews from Pocket Gamer and TouchArcade praised the game’s quality on mobile devices. However, Pocket Gamer noted that the game’s controls were difficult to use on touchscreen devices because the game requires precise and fast movements.

On April 25, 2019, one week after Katana Zero launched, Stander announced plans to create free downloadable content (DLC). He aimed to make the DLC’s quality equal to the main game. The DLC grew larger during development, reaching three times its original size by February 2020 and six times by March 2021. Despite this, Stander intended to release it for free. The DLC will be slightly more than half the size of the base game and will add new mechanics, enemies, and story elements. Stander described it as "more like Katana 1.5" than traditional DLC. He explained the DLC will resolve some plot points and expand the game’s world, but it will not finish the story. Stander plans to continue the story beyond the DLC and has outlined its ending. In May 2020, he mentioned that future games might connect to the game’s fictional universe.

On April 10, 2025, a teaser trailer for the DLC was released. It confirmed the DLC is still in development and will remain free when released. The release date has not been announced.