Katana Zero

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 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. 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 was developed over six years by the indie game creator Justin Stander under the studio name Askiisoft. It was Stander's first commercial game; his previous projects, such as Tower of Heaven (2009), had been smaller freeware games. After seeing the success of Terry Cavanagh's VVVVVV (2010), Stander concluded audiences only pay attention to indie games if they are being sold. Cavanagh, like Stander, had started off making freeware games, but none were as successful as VVVVVV.

Katana Zero originated from Stander's desires to create a larger project that could be sold commercially and tell a story. He began working on it in 2013 as a hobby during his sophomore year at McGill University. He used the GameMaker Studio 2 game engine and spent the first two years building simple prototypes. The game was a means of expression for Stander outside schoolwork and he spent most of his time at college developing it.

Katana Zero received "generally favorable reviews" according to the review aggregate website Metacritic, and a "Mighty" approval rating from OpenCritic. Critics considered Katana Zero stylish and well designed. IGN said it "refines the tried and true one-hit-kill formula in a manner that makes it feels fresh, exciting, and innovative", while Nintendo Life and Nintendo World Report considered it a standout in the Nintendo eShop library. Destructoid's reviewer said Katana Zero was "bleak, beautiful, bloody, and brilliant" and changed how he viewed video games.

Critics praised the 16-bit visuals. They enjoyed the retro VHS aesthetic and visual effects—though some wrote their intensity could induce headaches—as well as the amount of detail in the sprites and animations. IGN found the lighting effects impressive and said they worked with the "slick neon aesthetic and fantastic sprite work" to give the game personality. GameSpot appreciated that Katana Zero did not use a retro aesthetic simply for nostalgia, and alongside Polygon found the detailed sprite work and smooth animations added emotional weight.