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Kaizo (Japanese:改造,Hepburn:kaizō; meaning "modification", "rebuild", "remodel" or "reconfiguration") is a philosophy ofgame design, specificallyplatforming games, distinguished by a high degree of strictness placed upon the player's intended actions and movements through a level.^[1] This emphasis on precision, which manifests in the form of extremely-precise character movement (often enforced through subterfuge and purposefully hidden traps), requires the player to use high levels of skill and knowledge of the game's physics andengine in order to accomplish tasks. The philosophy is most closely associated withROM hacks ofSuper Mario World and with custom levels created inSuper Mario MakerandSuper Mario Maker 2, but has been cited as an influence in other fan-made and original game designs.^[2][3]

The term originally came from the Japanese ROM-hacking scene, wherekaizo was used as a general term for all modified games.

The creation of ROM hacks forSuper Mario games began in 1987 with the release ofTonkachi Editor [ja], ahex editor for theFamicom Disk System.^[4][5]While the program did not achieve commercial success, it included on itsfloppy disk a demo feature to modify a disk copy ofSuper Mario Bros., turning it into a ROM hack calledTonkachi Mario which can be considered a precursor to similar projects. The editor's official documentation, released in instalments, also frequently referenced Super Mario Bros. for practical examples, documenting its structure.^[6]Like later established hacks,Tonkachi Mario requires the player to be dedicated to understanding the quirks of the game engine, such as knowing about bugs in the programming in order to be able to pass through walls that are normally impassable.^[7][8]

Kaizo Mario World was released in 2007 by T. Takemoto on the Japanese platformNiconico.^[7] The first hack to officially use the phrasekaizo in the title, it introduced many elements that would become synonymous with the design style: "kaizo blocks"—invisible blocks that are placed precisely where a player believes they should jump in order to punish their assumption, auto-scrollers that constantly increase in speed, post-goal obstacles (known as "kaizo traps") that require the player to take a specific action before finishing, and "Ultra Star": a level consisting of extremely precise platform jumps and switches.

T. Takemoto's video on NicoNico was reuploaded and shared on English-language websites under the titleAsshole Mario, and became a viral hit due to the extreme demands of the player and the humor in discovering all of the hidden traps. The firstLet's Play has over 5.5 million views onYouTube,^[9] and Takemoto released sequels in 2008 (Kaizo Mario World 2) and 2012 (Kaizo Mario World 3), with the latter in particular being considered one of the most difficult ROM hacks to date, mainly due to the heavily modified Bowser fight which is based on random factors.

Many experienced players at the time assumed that the games were unlikely to be played through by human players, if at all, and that it was primarily a genre fortool-assisted speedrunning.^[7] As the games became more popular and accessible, however, more experienced players within theSuper Mario Worldspeedrunning community began to attempt the games as a way to challenge their skills and break the monotony of record grinding. This led to the feature ofKaizo Mario World 1 by dram55, a world-class runner ofSuper Mario World atAwesome Games Done Quick 2015 in 24 minutes and 36 seconds.

This run served as the springboard for the inclusion ofKaizo Mario World,Super Mario Bros. 3, andSuper Metroidfangames in following events, including notable runs byGrandPooBear,^[10] MitchFlowerPower,^[11] Oatsngoats,^[12] and individual and relay races of both full hacks and custom-created levels. Kaizo inclusions in GDQ events have served to inspire many to both play and create kaizo games, as well as generate media for both the marathons^[13] and the community.^[14]

The ability for a player to make and play their own kaizo-style levels was extended to a much wider audience with the release ofSuper Mario Maker in 2015. Prior to this, all games such asKaizo Mario World were made usingLunar Magic, aSuper Mario Worldlevel editor, and distributed non-commercially via patches to players who applied them to legally owned copies of the game and played them viaemulator or through custom cartridges.^[15]

WithMario Maker, creative tools were given directly to players, along with the distribution and means to share and access creators and levels quickly. This, combined with the high sales for the game worldwide,^[16] led to a surge in interest in Kaizo, as well as an influx of players and creators looking for people to showcase their work. Early examples of Kaizo levels reaching notable mainstream attention include the creations ofPangaeaPanga, whose "Pit of Panga" series of levels, including "P-Break"^[17] and "U-Break,"^[18] would set records for playthroughs, clear rate, and viewership.

As Kaizo's popularity first started due to views and playthroughs uploaded to Youtube, it has continued in part through livestreaming and community participation on platforms such asDiscord andTwitch.

As the creation and distribution of ROM hacking is legally unable to becommercially monetized, many creators also participate in playthroughs and livestream events. Creators and players also come together to share new hacks, resources, and to mentor and encourage new creators within the genre.Kotaku describes the community as "friendly, competitive, and creative" with famous players alongside new players.^[19]

The popularity of the subgenre remains strong, especially on video platforms such as Twitch andYouTube. Well-known content creators, such as BarbarousKing, GrandPooBear, ThaBeast721, CarlSagan42, ryukahr, Shoujo, and PangaeaPanga, have several hundred thousand subscribers and regularly have thousands of live viewers.

Thekaizo series ofPokémon games (especiallyEmerald Kaizo) started to grab the attention of YouTubers and Twitch streamers in 2019–2020, as channels such as ChaoticMeatball and zwiggo started to upload challenge runs using mono-typed teams and other restrictions. These games are known for having enemy trainers with complicated teams and movesets, forcing the player to fight most trainers, who are often optional in the original games, and limiting resources for the player. This includes preventing them from using healing items in battle, only allowing them access to under-powered Pokémon against much stronger enemy teams, and limiting access to powerful moves such as stat-boosting moves, forcing them to strategize against enemy teams rather than casually play through the game. They are also known for having difficult and complicated overworld puzzles. Otherkaizo games includeBlue Kaizo andCrystal Kaizo, while advanced difficulty ROM hacks such asFireRed hack "Radical Red" andEmerald hack "Run & Bun" are often associated with thekaizo series due to their similar level of difficulty.

In May 2022, the YouTube channelPokémon Challenges uploaded a video titles "How I Beat the Hardest Pokémon Game Ever Made", detailing his 151st (and final) attempt to beatPokémon Emerald Kaizo while following the "HardcoreNuzlocke" challenge rules, meaning he had to permanently store all fainted Pokémon, only catch the first encounter in each area, keep his Pokémon levels under a self-imposed cap, and restart the run should he lose a battle. This video features other YouTubers such asWolfeyVGC andJaiden Animations and has accumulated over 7 million views. Since his victory, multiple streamers and YouTubers, such as WolfeyVGC, have also completed "Hardcore Nuzlocke" challenges ofEmerald Kaizo and beating the game has become a status symbol within the Nuzlocke community. In February 2023,Twitch streamer Prouty completed a "Hardcore Nuzlocke Deathless" challenge ofEmerald Kaizo, meaning that not a single one of his Pokémon fainted during his run. This run was celebrated by Pchal, who made a video in December 2023 breaking down this run.

The primary attribute ofkaizo design philosophy is restriction - in contrast to regular platforming games, where players may have freedom to repeat and try multiple techniques to reach the desired objective,kaizo design intentionally focuses on taking away time and opportunity from the player in order to force a specific solution and specific method of execution.

Beekaay, an SMW Central moderator, explains the motive and intent behindkaizo design as follows:

In general, Kaizo hacks are unforgiving. They don't have sprinkled power-ups throughout the level to allow you to get hit and keep going. Missing a jump or getting hit by an enemy results in a death. If there is a mushroom in a level, it has a specific purpose, such as for breaking spin blocks or damage-boosting through some munchers, and you will not have it past a point determined by the author.^[20]

A hallmark ofkaizo gameplay is the frequent and repeated death of the player in the course of the playthrough, even by highly skilled players. This constant cycle is considered part of the learning process, and manykaizo games do not punish the player beyond a forced restart (that is, there is no reduction of score or limit on total lives).

Game design,^[21] mass communication, humanities,^[22] and new media scholars^[23] have usedkaizo design philosophies as a subject for analysis in the relationship between players, level designers, audiences and the motivations and rationale for making and playing video games.^[24]

Wilson and Sicart consider thekaizo philosophy among examples of "abusive design" in video games—a deliberate, violent break with established conventions in game design and a resulting artistic approach to the medium:^[25]

The "true" game, as exemplified by games like Kaizo Mario as described above, is not about mastering the system, but about knowing the designer. Therefore, the activity of play is not instrumental or tool-oriented, but productive and oriented towards the intersubjective. Play, in our view, is only productive in dialogue.

At present, more than 988kaizo hacks of varying difficulty have been approved by SMW Central, which has hosted and approvedkaizo hacks since 2014.^[26]

• SMW Central - Primary home for Kaizo Super Mario World hacks and resources
• Maker Teams - Hub for Kaizo Super Mario Maker creators of varying interests and subgenres
• Metroid Construction - Primary home for Super Metroid hacks and resources

• Fan games
• Mario video games
• Unofficial works based on Mario
• Video game modding
• Video game genres

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