|“||Pale summer moonlight shimmers on the seafloor.
An octopus, unaware that dawn will bring capture,
Rests within a trap, dreaming fleeting dreams...
— The opening poem of Octo Expansion
The mode is located at the subway entrance in the alleyway to the upper right of the map. It is also referred to as the Deepsea Metro on the drop down map.
The player takes the role of Agent 8, an Octoling with amnesia who finds themself in a strange subway station connected to a series of research facilities deep underground. As the game stars, the Octoling sees Cap'n Cuttlefish ready to attack them before stopping seeing that they don't have a weapon with them. Cap'n Cuttlefish then informs the Octoling that they and Agent 3 fought in Octo Valley before "something" attacked the three and caused the Octoling to lose all of their memories in the process. Surprised, Cap'n Cuttlefish asks if they remember anything which prompts the customization of the player's Octolings. After finding a way through the beginning, Agent 8 and Cap'n Cuttlefish come across an empty platform with a lone telephone ringing. As the Octoling answers the telephone, the telephone identifies them as subject No. 10008; being too long, Cap'n Cuttlefish decides to give No. 10008 the name, "Agent 8" for short. It tells the Octoling that it would want to go the "Promise Land" so they can be free, but in order to do so, Agent 8 must collect the 4 "thangs" so they can have a way to the promise land. As the phone ends the call, a train pulls up towards Agent 8 and Cap'n Cuttlefish and stops for them. They then meet C.Q. Cumber who is the conductor of the train and explains the functions of the CQ-80 and the credits system. Shortly afterwards, Pearl and Marina make contact with the two of them and offer their help in escaping.
After collecting all four "thangs", the telephone cryptically asks whether Agent 8 is "ready to ascend to a higher plane of existence" and "willing to become something greater than yourself" before using the thangs to seemingly open a door out of the Metro. It is soon revealed to be a trap, however, and Agent 8 and Cap'n Cuttlefish realize the thangs were parts of a giant blender that the Telephone plans to use to render them into raw material.
Before the blender can turn on, Cap'n Cuttlefish is able to send a distress call, prompting Agent 3 to crash through the ceiling and destroy the blender. Agent 3 is knocked out, but Agent 8 is able to use Agent 3's employee-model CQ-80 to activate an elevator to the surface after a lengthy escape, defeating a partially sanitized Agent 3 in the process. Once on the surface, Pearl and Marina prepare to airlift the Cap'n and Agent 8 to safety, but the above-ground section of the facility proceeds to rise from the ground, now revealed to be part of a human statue. The telephone introduces itself as Commander Tartar, an AI created 12,000 years ago to pass on human knowledge to any species worthy enough. The Commander has judged both Inklings and Octarians as unworthy of receiving its knowledge, and begins activating a weapon to destroy and recreate life on Earth, fueled by the raw material of the failed subjects that it seeks to use to create "perfect" life. Marina, Pearl, and Agent 8 hurriedly put a stop to the statue, using Marina's prototype "hyper bombs" and a Killer Wail powered by Pearl's loud voice. With the day saved and Commander Tartar destroyed, Pearl and Marina hug with Cap'n Cuttlefish celebrating and Agent 3 wakes up, Agent 8 watches and smiles at finally able to be free. The group then look out to Inkopolis Square, Cap'n Cuttlefish presses the CQ-80 and the staff credits play. After the credits begin to finish, Agent 8 looks back at the player and smiles at them. With the day saved, Off the Hook returns to Inkopolis Square, dropping off Agent 8 there as well.
When Agent 8 returns to the Deepsea Metro, C.Q. Cumber tells them that they can now transfer credits into items as well as find Mem Medallions in different Stations that can be used to exchange items in the Vending Machine. Cap'n Cuttlefish informs Agent 8 that Agent 3 went out on patrol and he wished to check on the denizens of the deep for a while longer.
After Agent 8 completes all the tests, a locker in the Central Station will open and Agent 8 will have a battle with their "Inner Agent 3" with both of them having the classic colors of blue and orange respectively. Defeating them will reward the player with the Golden Toothpick.
Octo Expansion adds a new single-player campaign consisting of 80 levels. Off the Hook will support Agent 8 from above ground, and their help can be used to skip missions that are too difficult.
The first station has the Telephone, where Agent 8 learns the details on how to escape the Deepsea Metro. The Telephone also provides Agent 8 with the CQ-80 device (a flat controller shaped like a submarine), used to navigate the underground; and a CQ Card, which is used to store CQ Points. C.Q. Cumber will issue an initial 1,000 CQ Points to start off.
Entering each mission costs a set amount of points, for either 1, 3 or 5 lives. The player can then choose between multiple challenges, each with a different weapon set. Depending on the weapon set chosen, a different amount of points is awarded (harder sets provide bigger rewards).
Lives are lost not only from being splatted but also by failing to comply with certain test conditions. If the player fails to complete the test's conditions to pass, an inflatable balloon of ink attached to Agent 8's ink tank will explode and splat them in the process.
If the player loses all of their lives, they may continue from the last checkpoint with all lives returned by paying more points, return to the station for free (but still having to pay to reenter the level), abandon the level and return to the subway, or ask for help from Off the Hook to skip the level. Off the Hook can only help you skip a level if Agent 8 fails the levels at least twice. When prompted to Ask for Help, it requires the regular fee to autopass the level and Marina will download Agent 8's test data and hack into Kamabo's mainframe to trick the data into thinking Agent 8 passed, the screen will have rows of Marina's logo overlayed on it and the mem cake will be gray with only the quote "Your guess is as good as mine." However, if pressed to ask for help, the player can press "X" again to "Tough it Out" and continue to play the level as normal. If skipped, the mem cake of that level will not be collected barring players from certain rewards till they've completed the station properly.
If a player finds themselves with less than 100 CQ Points after losing all of their lives, a game over screen will appear instead of a continue screen. The player will then return to the subway where Pearl will take money from her Dad and Marina will convert the money into CQ points and will transfer 3,000 CQ Points to Agent 8. However you will be in debt which can be repaid through Cap'n Cuttlefish. Players cannot access the secret boss fight if they have debt.
Enemy Octolings will be able to use more main weapons and special weapons, only seen in online multiplayer modes until now. For example, in the first mission (also seen in the trailer), an enemy Octoling is shown chasing Agent 8 using an Inkjet. A select amount of levels will also be special only, meaning Agent 8's special bar will never go down.
Some Tests have Agent 8 go against a team of four Sanitized Octolings in a style of ranked modes. The time limit will always be five minutes and Agent 8 has unlimited lives until the time limit ends.
After completing the campaign, players will be able to play as a male or female Octoling in multiplayer gameplay and customize them just like Inklings. Gear and weapons will be shared between the characters in the same account.
A short gameplay video of one of the missions was published on April 30, 2018. It shows Agent 8 on a mission requiring her to defeat all enemies within 2 minutes. The enemies are Sanitized Octotroopers, Octosnipers and Octocommanders situated, along with Balloon Fish on floating platforms, which Agent 8 can make spin by shooting her Splat Charger at Ink Switches. This video also marks the first appearance of canisters similar to the special weapon canisters from Octo Canyon, as well as metallic briefcases. Both are marked with the same logo as the CQ-80 and the CQ Card, unlike the Octo Canyon canisters that show the Ammo Knights logo. The objective of the missions were revealed in a short gameplay video of Stamped-Up Station. It is a set of three floating pieces of a goal that must be covered in ink to be activated and be touched in order for the level to be completed which the level will say "TEST PASSED!" similar to the function of the Zapfishes. There are also smaller posts that emit red beacons that function the same to Mini Zapfish.
After 3 of the thangs are found, Cap'n Cuttlefish will decide to make a "missing" poster for Agent 3, he will then ask Agent 8 what they look like which determines Agent 3's gender, skin color, and eye color.
During the escape, if Agent 8 dies five times in a phase, their "Skip Charge" will be filled and will be allowed to skip the phase. If so, the sounds of a Splashdown and a Sting Ray can be heard and there will be a simple transitional phrase on the screen stating that Agent 8 got past the phase. In the final boss, it will be instantly filled.
When Agent 8 returns to the Deepsea Metro, they will now be able to use the Vending Machine in Central Station to exchange 15000 Credits for an item and go around other stations to claim Mem Medallions to be exchanged for the Vending Machine. The Vending Machine has more variety than the Ammo Knights Enhancifier, having the chance of getting more than one drink ticket, upgraded food tickets, Cash, Ability Chunks, Credits. The items range from getting every type of drink ticket to even getting tens of thousands of Cash.
- Cap'n Cuttlefish
- Agent 3
- Agent 8
- C.Q. Cumber
- Iso Padre
- Denizens of the deep
Purchasing the Octo Expansion unlocks the Studio Octophones and the Octo Layered LS. As soon as the player enters the game and finish the Inkopolis Square News, a box containing both pieces of gear will be in the center of the Square.
14 gear items are obtainable through Octo Expansion. All players will see the items in-game, but only players who purchase the Octo Expansion will be able to obtain the items for themselves.
Of all the items listed here, only the Golden Toothpick requires the player to pass all stages without help from Off The Hook.
A video showing the Studio Octophones and Octo Layered LS being received by the player. (link to file)
- Main article: Music
The full version of the Octo Expansion trailer song, called "Nasty Majesty" was performed during Off the Hook's live concert at NicoNico Choukaigi 2018. On 21st May 2018, a new character was revealed. Her name is Dedf1sh and she is a Sanitized Octoling DJ. According to Nintendo, Dedf1sh was an DJ with a promising future in the music world. During her search for inspiration, she came across a deep-sea testing facility and became disinfected. Despite this, she kept up her career as a DJ, and her music will be heard all through the facility.
|Nasty Majesty(NA/EU/OC)[a] / ナスティ・マジェスティ(JP)[b]||Off the Hook(NA/EU/OC)[a]/テンタクルズ(JP)[b]|
|Fly Octo Fly ~ Ebb & Flow (Octo)(NA/EU/OC)[a]|
|Into the Light(NA/EU/OC)[a]|
|Central Station||Gnarly Rails Station||Far-Out Station||Wassup 8-Ball Station||Roll Out Station|
|Promise land here we come!||Ride on!||Blast from the past!||Signs point to yes...||Baller status!|
|Fake Plastic Station||Bounce with Me Station||Maverick Station||Bumpin' 8-Ball Station|
|Looks like the real thing...||Nice air, bud!||Revvin' up your Inkjet...||Better not tell you now...|
|Wassup 8-Ball Station||Poppin' Fresh Station||Spin Docto Station||Rad Ride Station||Wack 8-Ball Station|
|Signs point to yes...||Grind it out!||Just go ahead now...||Just cruisin'...||It is decidedly so...|
|Notorious Station||Fly 8-Ball Station||Righteous Rails Station||Grab & Go Station||Ink 'n' Slide Station|
|Blowin' up like it's all good.||You may rely on it...||Gnarly grindage!||Here lies the foundational thang...||Furl realz!|
|Tubular 8-Ball Station||Brute Rollup Station||Phat Splatz Station||Breakdance Station||Ink from Above Station|
|Outlook not so good...||Rock 'n' roll 'em!||Bring da ruckus!||Step it up!||Heads up missiles up!|
|Pop Rock Station|
|As 50 yellow balloons go by...|
|Radical Rails Station||Shrinky Ink Station||Bumpin' 8-Ball Station||Move It Move It Station||Stamped-Up Station|
|Mondo grindage!||Dink and dunk!||Better not tell you now...||Ya like to...||Stamp-collaborate and glisten!|
|Bust 'n' Move Station||Totally 8-Ball Station||Right Round Station||Bodacious 8-Ball Station||McFly Station|
|Don't just stand there...||Reply hazy. Try again...||Round round round round...||As I see it, yes...||Do it with some style!|
|Abracadabra Station||Matchmaker Station||Smash & Dash Station||Stick 'n' Move Station|
|Now you see me...||What's up, dog?||Here lies the precision thang...||Float like a butterflyfish...|
|Ink from Above Station||One-Shot Station||Slap Bracelet Station||Mad Props Station||All That 8-Ball Station|
|Heads up missiles up!||Do not miss your chance...||2 cool 4 school.||Spin to win!||My sources say no...|
|Radical Rails Station||Targetbuster Station||Girl Power Station||Goose Station||Labyrinth Station|
|Mondo grindage!||Who you gonna call?||Ink-a-zig-ah...||Listen to its howlin' roar...||Splat magic splat!|
|Ink & Watch Station|
|Watch out now!|
|No Whammy Station||Bust & Run Station||Don't Ralph Station||Heinous 8-Ball Station||Hypercolor Station|
|Don't stress your luck...||Here lies the surrounding thang...||Gettin' dizzy with it...||Cannot predict now...||Ink on, ink off...|
|Swass 8-Ball Station||Iceman Station||Da Bomb Station||Squee-G Funk Station||Cratebuster Station|
|Don't count on it...||Jet into the danger zone...||Splat Bomb diggnity!||Inkulators, mount up!||Ain't afraid of no crates.|
|Bodacious Rotation Station||Drop the Bass Station|
|Don't get psyched out!||Stomp 'til you drop.|
|Drop the Bass Station||Slow Ride Station||Pop Star Station||Stamped-Up Station||Popalicious Station|
|Stomp 'til you drop.||Take it easy...||Don't stop 'til you pop enough!||Stamp-collaborate and glisten!||The fun don't stop!|
|Duh-Oh Station||Matchmaker Station||Jump Station||Bring It Station||Cubular Station|
|Who let the pods out?||What's up, dog?||Might as well...||Pound the rock!||What's the dealio?|
|Toastmaster Station||Hasta La Vista Station||House Party Station||Ink 'n' Slide Station||Bustalicious Station|
|Y'all bready for this?||I know now why you ink...||No kiddin' or playin'.||Furl realz!||Did I do that?|
|Gnarly Rails Station||Ride with Me Station||Freakazoid Station||Wack 8-Ball Station||Iceman Station|
|Ride on!||Shotgun!||Mad skillz, yo!||It is decidedly so...||Jet into the danger zone...|
|Slap Bracelet Station||Ballercise Station||Sweet Ride Station||Shooter McStation||Ink It Station|
|2 cool 4 school.||Feel the burn!||Easy, breezy...||Just innnk it in...||Ink it real good!|
|Break & Bounce Station||Cool Your Jets Station|
|Here lies the sealing thang...||Whatever, Dad!|
|Toastmaster Station||Dinky Ink Station||No Whammy Station||Can't Touch This Station||Righteous Rails Station|
|Y'all bready for this?||Shrink and sink!||Don't stress your luck...||My my my my...||Gnarly grindage!|
|All Eyez Station||Ride with Me Station||Radio Station||Poppin' Fresh Station|
|Can't c me...||Shotgun!||Ten-four, good buddy!||Grind it out!|
|Cool Your Jets Station||Matchmaster Station||Girl Power Station||Footloose Station||Stick 'n' Move Station|
|Whatever, Dad!||Break it down!||Ink-a-zig-ah...||Watch your step!||Float like a butterfly...|
|Ink & Watch Station||Outrageous Station||Whack-Fu Station|
|Watch out now!||Truly, truly, truly.||Whack attack!|
|01. Coccyx Phase||02. Villi Phase||03. Belly Phase||04. Intestinal Phase|
|05. Diaphragm Phase||06. Peristalsis Phase||07. Spinal Phase||Turf War|
|View the quotation page.|
- The expansion costs $19.99* in the US, €19.99 in the EU, £17.99* in the UK and ¥1800* in Japan. It is the first paid downloadable content announced for any game in the Splatoon series.
- Studio Octophones and Octo Layered LS were available early by pre-purchasing Octo Expansion. This is a throwback to the initial Splatoon Global Testfire, where players who pre-purchased Splatoon during the event were given Studio Headphones and a special squid-themed layered shirt.
- The various Phases during the escape are named after internal human body parts and are also placed roughly where the parts are situated in a human body. These places are revealed to be inside the NILS Statue, which resembles a human being.
- Several references to the number eight are made, such as:
- "Splatoon 2: Octo Expansion" is eight syllables long,
- Agent 8 (subject No. 10008) as the main protagonist,
- Using the CQ-80 device to navigate Deepsea Metro,
- Having eighty levels,
- The tubes on the sides of the checkpoints resemble the number eight,
- The poems for mem cakes have eight syllables for each line,
- The ball the player has to push is an eight ball,
- In a level the player has to collect eight data-points,
- If the player goes through the lines in alphabetical order the last thang is on the eighth line,
- The escape has eight phases if you count the final boss fight.
- At the end, when Pearl uses the Killer Wail against the NILS statue, the ink turf covered for Good Guys goes up to 888.8 % high.
- The five music tracks from the Octo Expansion are numbered from 80 to 84 in Squid Beatz 2.
- The locker that has Agent 8's memories in it, which are used to enter the Secret Boss fight, is locker #8
- Unlike Marie and Sheldon, Cap'n Cuttlefish and Off the Hook are aware of Agent 8 being splatted or failing tests as they give advice to them when they respawn or react to them messing up as well as having unique dialogue when using different weapons.
The Telephone speaking to Agent 8. The text reads: If you have come here... ... You're trying to depart for the promised land, aren't you?!
Smokestacks rising from one of the Deepsea Metro station, similar in appearance to underwater magma vents
Promotional image of Off the Hook's new looks for the expansion.
Agent 8 inside a mission
Agent 8 standing in front of a mission entrance gate
Agent 8 being thrown at the checkpoint at the start of a mission.
The option at the bottom right shows Off the Hook's icons and reads " Ask for help"
Names in other languages
Splatoon 2 Octo Expansion
|Dutch||Splatoon 2: Octo Expansion||-|
|French||Splatoon 2: Octo Expansion||-|
|German||Splatoon 2: Octo Expansion||-|
|Italian||Splatoon 2: Octo Expansion||-|
|Russian||Splatoon 2: Octo Expansion
Splatoon 2: Octo Expansion
|Splatoon 2: Octo Expansion
|Spanish||Splatoon 2: Octo Expansion||-|
- North America, Europe, and Oceania