Splatoon 4 Story Mode: Complete Campaign Walkthrough & What We Know So Far

Look, I know it's weird to write a walkthrough for a game that hasn't been announced. But the Splatoon campaigns follow a pretty clear formula, and knowing how previous games handled their story modes is actually the best way to prepare. If Splatoon 4 sticks to Nintendo's pattern, the campaign will be roughly 25 to 30 levels spread across a hub world with hidden collectibles, boss fights, and a final showdown against whatever threat the Octarians (or someone worse) cooked up this time.

Let me walk through what a typical Splatoon campaign looks like, because if you've never played one, the structure is surprisingly unique.

The first thing you'll do is pick your character, Inkling or Octoling. This has been a thing since Splatoon 2's Octo Expansion, and there's no way Nintendo drops it now. Your character is Agent 3 (or Agent 3's successor, the numbering in this series is honestly confusing at this point) and you're recruited by Cap'n Cuttlefish or a new guide character to deal with a threat, typically involving stolen Zapfish or, in Splatoon 3's case, fuzzy ooze and a rocket ship.

The hub world is where Splatoon single-player really shines. In Splatoon 3, Alterna was this snowy wasteland dotted with floating platforms called kettles. Each kettle was a level. You'd walk around, find kettles, clear them, and unlock more areas. It's basically a linear campaign disguised as an open world. The hub itself had secrets, hidden items, lore artifacts, upgrade stations. You could spend a good chunk of time just poking around the hub finding stuff the level select screen wouldn't tell you about.

I actually liked Alterna more than Octo Canyon from Splatoon 2. Octo Canyon felt like a series of disconnected platforms. Alterna had atmosphere. Snow falling. Crumbling human ruins. This haunting sense that you were walking through what was left of our world after the apocalypse. Splatoon's lore is way darker than the colorful aesthetic suggests.

Anyway. Levels in a Splatoon campaign are usually 3 to 8 minutes each and each one teaches or tests a specific mechanic. One level might be pure platforming with ink rails and sponges. Another might have you using a Splatling to stop waves of Octarians. Another might be a stealth section where getting spotted means instant death. The variety is the point. They're designed to make you better at the game without feeling like a tutorial.

The weapon selection within levels is something people don't talk about enough. In Splatoon 3's campaign, each kettle gave you a specific weapon or let you choose from a small set. Some of my favorite levels forced me to use weapons I'd never touch in multiplayer. The Bamboozler level in Alterna completely changed how I think about chargers. By the end of it I wasn't good with the Bamboozler. But I understood it. And that's kind of the point.

Levels also have hidden Power Eggs scattered around, which are basically the campaign's internal scoring system. You don't need them to progress. But finding enough of them can unlock bonus gear or concept art in some games. The completionist in me loves it. The impatient part of me has definitely beaten a level with three eggs out of ten and never looked back.

Each area of the hub typically has a boss at the end. Splatoon bosses are almost always Octarian machines, giant mechanical faces with tentacles, weak points that open up after you dodge their attack patterns. DJ Octavio is the series mainstay, usually the final boss in his giant mech remixing the music as you fight. The Octo Expansion and Splatoon 3 both broke this formula in interesting ways, introducing more varied boss designs and phases.

Splatoon 3's final boss is worth talking about because it sets a high bar for what Splatoon 4 could do. Without spoiling too much, you fight Mr. Grizz in a spaceship. The arena moves. The music shifts. It's cinematic in a way Nintendo boss fights rarely are. If Splatoon 4's campaign tries to top that, we're in for something special.

Now. About Splatoon Raiders coming in July 2026 on Switch 2. This spinoff is going to tell us a lot about where the story is heading. Raiders teams you up with Deep Cut, Shiver, Frye, and Big Man, for an open-world treasure hunt in the Spirhalite Archipelago. That's new territory literally and narratively. Deep Cut were the Splatfest hosts in Splatoon 3, and giving them their own game suggests Nintendo wants to build them up as major characters before Splatoon 4.

My guess, and this is pure speculation, don't quote me, is that Raiders will introduce story threads that Splatoon 4 picks up directly. Maybe something about the crystals in the archipelago. Maybe a new faction. Nintendo loves seeding sequel hooks in their spinoffs.

As for collectibles in the campaign, expect Sunken Scrolls and Sardinium. Sunken Scrolls are pages of lore, how the Inklings evolved, what happened to humanity, the details of the Great Turf War. They're the best part of the campaign for lore nerds. Sardinium is the upgrade currency, used to power up your hero weapons at the upgrade station. Finding them all usually means replaying levels with different weapons or checking obscure corners of the hub.

One thing that tripped me up in Splatoon 3's campaign was that some kettles only appeared after you'd cleared certain other kettles. There was no indicator. You just had to walk back through old areas and notice something new. A little frustrating. Hopefully Splatoon 4 handles hidden level unlocks more clearly.

If you're trying to 100% the campaign, expect it to take somewhere between 8 and 15 hours depending on how good you are and whether you're hunting every collectible. The hero weapon replicas you unlock for completing every level with every weapon type are usually just cosmetic clones of the multiplayer weapons, so don't stress if you're not a completionist. But the lore from all the Sunken Scrolls? That stuff is genuinely interesting if you care about the world.

Real talk: I think the Splatoon campaigns are underrated. People treat them as a side mode before jumping into multiplayer, but the level design is consistently creative. Every level has one idea and explores it fully. That's good game design. If Splatoon 4's campaign is even half as thoughtful as Return of the Mammalians, it'll be worth your time.