Rumors and leaks

There are a few rumors and leaks regarding content inside Splatoon. Some of these are created by the community, while others are sparked by the developers themselves.

Ongoing
This is a list of rumors/leaks that have neither been confirmed true nor false.

Cheat code
Some days after the game's launch, players noticed that some Sunken Scrolls, as well as signs on Inkopolis Plaza, contain what appears to be arrows pointing up, down, left or right.

On the 9th of June, 2015, the official Splatoon Facebook page made a joke post referencing how some Facebook users accidentally type Google search queries on their Facebook profiles. This joke, however, sparked curiosity amongst fans, as the "search" was for "Squid Jump cheats". Naturally, Nintendo staff themselves would not be searching for cheat codes on a game made by their company, meaning the post was placed there on purpose, likely to hint players about the existence of a code hidden inside the game.

On top of this, the official Splatoon Tumblr account made a post about how players can press [ZR] on the Plaza to look around, and how this serves the additional purpose of getting information on Miiverse posts. It also mentioned that it "may also have another use", which remains unknown to this day.

As of yet, no code has been found, and it is unknown if there is any relation between the arrows, the rumored code, and the rumored extra function of the [ZR] button, or if any secret exists to begin with. Players have since been attempting to figure something out by input the arrow's directions during different parts of the game, mostly the Squid Jump minigame, but without luck.

(New) Super Mario Sunshine DLC
There is a new Super Mario Sunshine amiibo DLC rumor with several images. These images depict new Sunshine-related gear and Hero Mode missions.

Confirmed
This is a list of rumors/leaks that have been confirmed true.

Prima Strategy Guide "Coming Soon" section
The Prima Strategy Guide for Splatoon includes a "Coming Soon" section which shows off weapon and stage DLC. Some of this content still hasn't been released. Weapons: Carbon Roller, Custom E-Liter 3K, E-Liter 3K Scope, Inkbrush, L-3 Nozzlenose, N-Zap '85, N-Zap '89, Rapid Blaster Deco and Splash-o-matic. Stages: Bluefin Depot, Kelp Dome, Camp Triggerfish, and Port Mackerel. There are also two images of Tower Control, an upcoming Ranked Battle mode.

Datamine DLC leak
NWPlayer123 datamined Splatoon and leaked information about upcoming DLC weapons, stages, and modes. Also, some pictures and explanations about the new ranked mode games: Tower Control and Rainmaker.

The leaker also uploaded a video of the Sploosh-o-matic, one of the leaked unreleased weapons, after using live memory edits to add it in.

The following content was revealed due to this datamine:[Note]

Weapons

 * Sploosh-o-matic
 * Neo Splash-o-matic
 * N-ZAP '89
 * Custom Dual Squelcher
 * Luna Blaster
 * Carbon Roller
 * Octobrush
 * E-liter 3K Scope

Stages

 * Moray Towers

Modes

 * Rainmaker's description and gameplay mechanics

August DLC datamining
On the other note, someone datamined Splatoon and leaked more information about the Gatling Standard and the Ink Bucket, which was confirmed from Splatoon's Japanese commercial on July 25, 2015.

Busted
This is a list of rumors/leaks that have been confirmed false.

Super Mario Sunshine DLC
There was a "leak" on the internet that Super Mario Sunshine amiibo DLC was coming to Splatoon. Only a single image existed regarding this supposed leak. It has since been proven fake, with the author of the leak releasing the images they used to create it.