Splatoon 2

The game's development began shortly following the culmination of Splatoon's free content updates in October 2015. Its team sought to develop a worthy sequel to Splatoon, including new weapons and gameplay alterations to set itself apart from its predecessor. Set approximately two years after Splatoon, a decision made to enhance the fictional world's realism. Released on July 21, 2017. It received generally positive reviews, with critics commending its improved graphics and refinement of returning gameplay elements from its predecessor, though its online matchmaking and Nintendo Switch Online-restricted voice chat garnered criticism. A sequel, Splatoon 3, was released on the Nintendo Switch on September 9, 2022.

Like the previous game, Splatoon 2 is a third-person shooter with a focus on online multiplayer in which players control humanoid cephalopods, known as Inklings and Octolings, and use colored ink as ammunition to paint the surrounding area. Inklings and Octolings can morph between a distinctly humanoid form, during which they can walk and shoot ink using an assortment of weapons, and a cepholopodic form where they can quickly swim through ink of their own color and replenish their ink supply. During online matches, players are equipped with a "main weapon", their primary armament that allows them to spread ink. Each main weapon is assigned a loadout of one "sub weapon" and one "special weapon". Sub weapons are secondary munitions that require a considerable number of ink to dispense; they usually come in the form of defensive structures or offensive projectiles. Special weapons are powerful armaments that must be individually charged via the player's Special Gauge by inking the surroundings. Players wear in-game cosmetic gear that can be augmented with abilities such as being able to swim faster within one's ink and increasing ink ammunition capacity. There are a total of nine classes of main weapons to be chosen, seven of which return from Splatoon. Such returnees are Shooters, which are akin to automatic rifles; Blasters, a subclass of Shooters which fire in large bursts of ink; Rollers, which focus mainly on painting turf; Brushes, a subclass of Rollers that specialize in high surface mobility; Chargers, which are akin to sniper rifles; Sloshers, buckets of ink that specialize in close-range combat; and Splatlings, which are akin to Gatling guns. Splatoon 2 introduces two additional classes in the form of Dualies, dual-wielded weapons that allow the player to perform dodge rolls; and Brellas, shotgun-like weapons based on umbrellas that enable defensive maneuvers with folding shields.

Splatoon 2 sees the return of Turf War and Ranked Battles from its predecessor. The game adds League Battles as a tournament-structured version of Ranked Battles. In Turf War, players are divided into two teams of four as they compete to spread more of their colored ink across a battle arena after three minutes. Once players achieve level 10, they are granted access to Ranked Battles, alternative modes focusing on objective-based gameplay whose availability rotates throughout the day. Ranked modes regularly last five minutes, plus overtime if specific conditions are met. Splatoon 2 features four distinct Ranked modes, being Tower Control, Rainmaker, Splat Zones, and Clam Blitz, the latter being wholly new to Splatoon 2. Tower Control tasks players with guiding a mobile tower to a designated goal in the opposing team's base, clearing mandated checkpoints along the way. Rainmaker has teams carry a large weapon to the opposing team's base. Splat Zones plays similarly to king of the hill in that teams must exert control over a designated region of the map by covering it in ink for a specific duration. Clam Blitz tasks teams with collecting clams to hurl them into designated goals in the opposition's base to deplete a points counter. Collecting ten clams generates a Power Clam item, which is used to puncture the opposing goal and allow for depositing of clams. Whichever team brings the opposition's points counter to zero, or depletes it the furthest, wins.

Salmon Run is a co-op player versus environment mode first introduced in Splatoon 2. Salmon Run is available only on certain days at the Grizzco location. Players are allocated into a team of four and tasked to defeat hordes of hostile salmon enemies, named Salmonids, and deposit Golden Eggs to meet a designated quota for a particular "wave", of which there are three total. Golden Eggs are acquired by splatting large Boss Salmonid enemies that each have distinct attack patterns and weaknesses. Successfully completing matches advances the player's rank in Grizzco, with the mode's difficulty increasing in tandem with larger hordes of Salmonids and special events that otherwise augment a wave's challenge. Being splatted by a Salmonid results in the player being incapacitated until a teammate manually revives them. The match ends prematurely if all four team members are splatted at once.

The game features a single-player campaign called Octo Canyon, in which the player rescues captured Zapfish across various levels while fighting off evil Octarians. Unlike the previous game's single-player campaign which had a pre-determined weapon set, the player can now earn various weapons, some of which are required when playing levels for the first time. In addition to Sunken Scrolls that unlock artwork and in-game lore, players can collect Power Orbs to upgrade their Hero Mode weapons, and tickets that can be exchanged for temporary reward boosts in multiplayer battles, such as increased experience to level up quicker or more in-game currency. Using a single weapon to beat all of the Hero Mode levels grants the player a Hero Weapon Replica (identical to the campaign weapon) to use in multiplayer matches. Players can also play multiplayer online through an internet connection or play locally, although local play requires multiple consoles and copies of the game. The game also features LAN support with an adapter accessory for local private tournaments. The game supports amiibo figures, which allow players to store their character's custom look and unlock additional content. Free post-release updates and events are ongoing.

Once per month until July 2019, a "Splatfest" event was held in which players could choose one of two teams, usually based on common debates such as heroes versus villains and pancakes versus waffles. In addition, there were two collaborations during these Splatfests: Nickelodeon's Rise of the Teenage Mutant Ninja Turtles and Super Smash Bros. Ultimate. Splatfest themes were usually announced two weeks in advance, and players were given the ability to choose their team in the game's lobby. Themes were usually region-specific and happen at different times of the month. The only mode available in a Splatfest was Turf War, but players could choose between normal and pro modes. Winning battles awarded 'clout' to the winning team, and at the end of the Splatfest, the winning side was decided by evaluating popularity and clout earned in both battle modes. All players who participate earn rare rewards, but players on the winning team receive a slightly higher cut. In July 2019, Nintendo announced that the final regular Splatfest would be held that month. Bonus rematches of previous Splatfests were held in May 2020, August 2020, and October 2020. A Splatfest celebrating the 35th anniversary of Super Mario Bros. was held in January 2021.

The Splatoon series occurs on a post-apocalyptic version of Earth set some millennia following the extinction of humanity and subsequent rapid evolution of marine life. Splatoon 2 takes place two years after the events of Splatoon in and around Inkopolis Square. Like its predecessor, Splatoon 2 includes a single-player story campaign that follows the thieving of the city of Inkopolis' primary power source, the Great Zapfish, at the hands of the Octarian army. Another narrative event is the contemporaneous disappearance of Callie, one half of the celebrity musical duo the Squid Sisters, which the player character is also tasked with investigating. Splatoon 2's DLC expansion pack Octo Expansion occurs roughly around the same time as Octo Canyon. It is set in a subterranean train station named the Deepsea Metro, where an amnesiac Octoling falls into. At the direction of a talking telephone and with the assistance of Cap'n Cuttlefish, the player's guide from Splatoon who has also become trapped, Agent 8 seeks to ascend to the surface by clearing various testing facilities across the Metro to collect four objects known as "thangs". Completing the expansion's story awards players the ability to become an Octoling during multiplayer matches.

Octo Canyon takes place approximately two years after the final Splatfest of Splatoon, in which the pop idol Marie defeated her cousin and fellow Squid Sister, Callie. Having drifted apart in the months following the event, Marie worries that Callie was negatively affected by the result. After leaving Inkopolis to see her parents, Marie returns home to discover that the Great Zapfish that powers the city has gone missing, as has Callie. Cap'n Cuttlefish, the captain of the New Squidbeak Splatoon, and his understudy Agent 3 have traveled elsewhere. Fearing that the Octarians are once more involved, Marie assumes her role as Agent 2 of the Squidbeak Splatoon and recruits an Inkling, in lieu of Cuttlefish, from Inkopolis Square, the player character, to become Agent 4 and investigate. With assistance from Marie and weapons expert Sheldon, Agent 4 makes their way through Octo Canyon fighting the Octarians and recovering several stolen Zapfish, including ones powering the Octarians' machines. They discover that Callie herself has sided with the Octarians after being brainwashed by their leader, DJ Octavio, who is once again using the Great Zapfish to power his DJ stage, the Octobot King. Marie arrives with Sheldon and frees Callie from her mind control, allowing them to help Agent 4 defeat Octavio. With the Great Zapfish safely returned to Inkopolis and DJ Octavio defeated, the Squid Sisters happily reunite and resume their music career together.

The initial conceptualization of Splatoon 2 began during Splatoon's series of free content updates. Production began in full around October 2015 when these updates concluded. During this period, Splatoon's development team, including producer Hisashi Nogami, considered creating an upgraded version of the Wii U game as opposed to a full sequel. Nogami explained in an interview with Famitsu that they went against this in favor of creating a "legitimate sequel" that would reinvent Splatoon's mechanics in response to the title's positive reception among fans. To this end, the team included new main and special weapons, alongside additional gameplay configurations, mechanically different from those of Splatoon. For instance, the Dualie class and its dodge-roll ability was formulated to give players wholly unique gameplay experiences from the previous title. Another gameplay alteration was the reworking of the previous game's Super Jump to accommodate the Switch's lack of a secondary GamePad. On the game's worldbuilding, the team sought to convey a sense of realism by having time in the Splatoon series pass parallel to that of the real world. Splatoon 2 is set two years after the events of Splatoon, illustrated by the physical aging of characters and shifting of in-universe music trends. Lead sound designer Toru Minegishi intentionally developed music divergent in sound from Splatoon to symbolize progression of time, "creat[ing] it with the image of people now preferring different music than before." Nogami believed that this sense of change would inspire players to see the fictional world of Splatoon as "more real and present."

A limited-time global multiplayer demo for the game, known as the "Splatoon 2 Global Testfire", was released in March 2017. A special edition of Nintendo Treehouse Live was streamed during the first session, in which members of the Nintendo Treehouse participated in the demo. Similarly to the demo of the original game, it was only available to play for a specific time period, across six one-hour play sessions in one weekend. Another demo session demonstrating the game's Splatfest events was held on July 15, 2017. The game was released worldwide on July 21, 2017. In Japan and Europe, neon-green and neon-pink Joy-Con controllers and Splatoon-themed Pro Controllers were released alongside the game. A game card-free version, which features a download code inside a game case instead of a game card, was also released in Japan, as well as a Switch hardware bundle including a download code for the game. A similar bundle was released in the United States as a Walmart exclusive. New Amiibo figures of new Inkling Girl, Boy and Squid designs from Splatoon 2 were released alongside the game. These figures, alongside previous Splatoon figures, unlock exclusive in-game clothing and music tracks and allow the player to save a loadout of weapons and clothing to the figure so they can be readily accessed at any time. Characters with these saved load-outs can be posed alongside the player for taking screenshots. Amiibo figures of Pearl and Marina from Off the Hook were released on July 13, 2018, and feature similar functionality to those already released, while a final trio of figures of Octoling Girl, Boy and Octopus designs were released in Japan and Europe on November 9, 2018, and in North America on December 7, 2018. Like the previous game, Splatoon 2 was continually updated post-release with free content. From launch, at least one new weapon was added to the game almost every week, while new stages and game modes were added at irregular intervals. In late April 2018, this changed to having a large group of weapons added every month instead, with new stages continuing to be added until October 2018. While these regular updates were originally due to continue for around a year after the game's launch, with monthly regional Splatfest events being held for around two years, the regular updates were later extended to last until the end of 2018. An expansion pack for the game's single-player mode, titled Octo Expansion, was released on June 13, 2018. The game's content update in December 2018 was announced as the final one, albeit with balancing patches and Splatfest events due to continue into Summer 2019, but it was later revealed that more smaller updates would release until July 2019.

Prior to Splatoon 2's reveal, clips of the game were featured in the announcement trailer for the Nintendo Switch. Its unanticipated appearance led to speculation by the media and public over whether or not the footage shown was that from a port of Splatoon or a sequel. It was presented in the trailer akin to an esport, following investments by Nintendo in Splatoon esport tournaments in late 2016. Splatoon 2 was officially unveiled to the public during the Nintendo Switch reveal presentation held in Tokyo on January 13, 2017, where it was announced for release in Q2/Q3 2017. The reveal was accompanied by a trailer featuring the game's new maps and weapons, and an on-stage appearance of producer Hisashi Nogami in-character as a scientist from the Squid Research Lab, a fictional scientific group from the game, which appeared in various promotional material for the original Splatoon. Similarly to the first game, Splatoon 2 features Splatfest events that include crossovers with other brands, both from other Nintendo properties such as Super Smash Bros. Ultimate and third-party franchises including Teenage Mutant Ninja Turtles, McDonald's, Uniqlo, Nike, Sanrio, Meiji, and Pocky.

A manga series based on the game and illustrated by Sankichi Hinodeya began serialization in Shogakukan's CoroCoro Comic magazine in May 2017. It was published in North America by Viz Media in late 2017. A motion comic adaptation of the manga was announced in July 2017 and released on YouTube the following month. Splatune 2, a two-disc official soundtrack featuring music from the game by Toru Minegishi, Ryo Nagamatsu, and Shiho Fujii, was published by Enterbrain in Japan on November 29, 2017, debuting at number eight on Billboard Japan's Hot Albums chart. A second soundtrack album, Octotune, was released in Japan on July 18, 2018. This album features tracks added in the game's Octo Expansion DLC and other post-release updates, as well as a recording of the game's first live concert. It peaked at number five on the Hot Albums chart. Similarly to the first game, a series of real-life virtual concerts featuring the game's signature band Off the Hook have been performed in various locations. Their first concert was held at Tokaigi 2018 in Japan on February 10, 2018, a second was performed at Polymanga in Switzerland on March 31, 2018, a third concert which featured a new song, "Nasty Majesty" from Splatoon 2's Octo Expansion, was performed at NicoNico Chokaigi in Japan on April 28, 2018, a fourth concert was performed at Tokaigi Game Party 2019 in Japan on January 26, 2019, which featured more songs from the Octo Expansion, and was the first concert to only feature Pearl and Marina, and a two-day concert featuring both the Squid Sisters and Off The Hook was performed at Nintendo Live 2019 on October 13–14, 2019, which featured performances based on previous concerts.

Splatoon 2 debuted second on the UK software sales chart in its launch week, behind Crash Bandicoot N. Sane Trilogy (2017). It had 59% better first week sales than Splatoon and became the third biggest launch of a Switch game in that country. In Japan, Splatoon 2 sold roughly 670,955 copies at retail within the first few days of its launch. Including download copies, the game had sold over two million in Japan by early 2018, making it the first home console game to do so in the country since Wii Party (2010). The game shipped 1.56 million copies in Japan and 3.61 million copies worldwide in its first fiscal quarter on sale. By June 30, 2020, the game had sold 10.71 million copies worldwide, making it the ninth best-selling Switch game worldwide. As of December 31, 2022, Splatoon 2 had sold over 13.60 million copies worldwide, selling twice as much as its predecessor, and making it one of the best-selling Switch games.

Eurogamer ranked the game 17th on their list of the "Top 50 Games of 2017", while Polygon ranked it 43rd on their list of the 50 best games of 2017. The Verge named Splatoon 2 as one of their 15 Best Games of 2017. The game was nominated for "Best Switch Game" in both Destructoid's Game of the Year Awards 2017 and IGN's Best of 2017 Awards, the latter of which also nominated it for "Best Shooter" and "Best Multiplayer".

On February 17, 2021, during a Nintendo Direct, Nintendo announced a teaser trailer for Splatoon 3, which was released for the Nintendo Switch on September 9, 2022. The teaser trailer revealed gameplay similar to that of Splatoon 2, and revealed new items, weapons, and a new apocalyptic setting.