As Splatoon is primarily a multiplayer- based game, there is not much of a plot. However, the plot of the single- player campaign is as follows:
The protagonist, wearing the Hero Suit, travels through an underground world. The Octopus Army Corps, hoping to invade the Squid’s world, built an underground facility.
The game is an local/online 2- 4-player team shooter where the players try to take territory by splashing paint on the map. When the player is on their team's paint, the player can transform into a squid and travel inside the paint, which is twice as fast than if the player just walked on it. However, if the player is on the enemy's paint, the player moves slowly, and a paint effect appears the TV screen, similar to the blooper's ink effect in past Mario Kart games. You can also tap your team's icon to Super Jump to them, making it handy for ambushes. There is a variety of weapons for the Inklings to use as their main and sub weapons. The game also has "super weapons", which are more powerful than the normal weapons. (Ex. the bazooka, shield).
After three minutes, the match ends, and the team that has covered the most territory with ink wins. These matches are judged by a cat named Judd.
Inbetween sessions, the player wanders in a plaza area. There are other Inklings in the plaza based on player's own inklings and Miiverse posts. There are a couple shops where the player can buy weapons and customizations for their Inkling. They then can go to the mode of their choosing. These modes include Battle Dojo, a one- on- one local/ online mode in which the goal is to deflate as many balloons as possible; Ranked Battle, in which there are several variations on Turf War that you can choose from; the single- player campaign, in which you battle the rivals of the Inklings, the Octarians; and amiibo challenges, in which you can use the upcoming Splatoon amiibo to unlock challenges.
Main weapons are divided into 3 categories, Shooters, which fire rapidly in globs, Rollers, which sacrifice range for better ground coverage and overpowering enemies, and Chargers, which have low fire rates and to properly use, take a while to charge, but more power and more range than a shooter
The game launches with these 5 maps.
These maps will be added sometime later for free.
The game is divided into two main distinctions for Multiplayer. There is the unranked Multiplayer that consists of the game mode Turf War. The other is Ranked Battle, which consists of the other modes; Splat Zones, Tower Control and Rainmaker. Ranked Battles require a minimum level of 10 to be able to be used.
There is also a local multiplayer mode called Battle Dojo. It's only two players with one on the GamePad and the other on the TV screen. The two compete to see who pops the most balloons.
Inkopolis is the hub which the player uses to access the different modes. It also features an area called Booyah Base, which contains the shops.
The single-player is called Octo Valley and the player fights against the Octarian army in underground biospheres. The Octarian army has a variety of units at their disposal as well as series of platforming challenges. The Inkling puts on the Hero Suit and ventures to rescue the Zapfish in each level.
This is one of the first game put together by Nintendo's "garage" initiative, a program to get younger developers to create their own games.