Why can Inklings and Octolings only swim in ink that's their team color? It's because they'd only blend in with that background!
One of the members of the Chirpy Chips is a flapjack octopus, which may seem weird, considering that Inklings and Octolings are mortal enemies in the first game... until you find out that real flapjack octopi don't produce ink. The band (and Inkling society as a whole) accepted them because they couldn't hurt them!
Most of the Octarians are octopus tentacles. Real life octopodes have significant parts of their nervous systems in their arms, and the arms can even grow back if lost. So: perhaps the tentacle Octarians are cultivated from a "parent" Octarian/Octoling by chopping them off and letting them fight for Octo-kind, with the distinct possibility that they're harvested from the final boss.
One of the Sunken Sea Scrolls depicts a younger Octavio when it talks about the Octarians, indicating that humanoid Octarians and Octolings are the 'core' of their race.
Evidence that the final boss is using his own donor tentacles to clone up his forces? Take a good look at the tentacles that serve as the weak spots of the Great Octoweapons. Those scars on it are the same as his own.
More brilliance: The 'true' Octarians, already dealing with a crisis of living space, are unwilling to risk themselves on dangerous missions to steal Zapfish from Inkopolis, and so they make clone soldiers and such using their donor tentacles to beef up and mechanize their forces, only having their Elites take to the field as Octoling and Elite Octoling troopers.
Also, some of the Octarian troopers, especially the single-tentacle ones, are... noted for being fairly dumb, really. Well, no crap while the severed arms of an octopus do have a lot more neural mass than most limbs, the animal is still at its most intelligent when it has all its limbs and is connected to its brain. Of course the single-tentacle Octarians aren't bright, they're operating on limited brain power.
Confirmed in the official artbook.
The shed behind Cuttlefish in the main hub world is full of zapfish dolls, explaining where he got them to place into replayed levels.
In a meta sense, while the Boss Banter of the Final Boss is dratically different between the more serious European localization and the Large Ham American one, they still share one punny line: "Time to... D-D-D-DROP THE SEA BASS!!". Of course they wouldn't even think on having a game by the same creators of Animal Crossing without the obligatory "sea bass" pun; especially for a game entirely focused on sea creatures.
At first, you're likely going to wonder "Why the hell can't Inklings swim? Aren't they squids?", but then the reason why they can't will dawn on you: they're mostly made of ink, which dissolves in water.
Probably not the case. If you fall into void, you explode in mid-air, most likely to respawn into action as fast as possible instead of climbing all the way back up. Same with water they'd have hard time climbing out of it because they can't spray walls to climb out because, well, ink and water, and rather self-destruct and respawn than swim (which they apparently can't) to where they can climb out normally, only to be splatted when they're most vulnerable. Time is golden in turf wars.
This explanation isn't quite as viable in the single player campaign as you're not under any sort time-limit, but you still fall apart if you happen to fall in water. Cuttlefish even comments how you can't swim. So the fact that Inklings are mostly composed of ink seems to be the reason they can't swim.
Indeed, Word of God has explicitly confirmed that Inklings canonically do dissolve in water, and yes, precisely because they're made of ink (specifically, their "skin" is so thin and porous that dunking them in water will cause them to basically "bleed out" due to osmosis).
The Octolings and Octostriker stages in single-player involve a group of Octarians invading certain areas of the surface; then how come Agent 3 is the only one there to stop them? Well, these stages take place either at night or what seems to be dawn. Remember how one of the earlier Sunken Scrolls said that, during the start of the Great Turf War, Octarians were winning because Inklings couldn't wake up early enough in the morning to defend themselves? A century worth of history or not, some things just don't change. If anything, it makes Agent 3 more impressive as they have the fortitude to be up at that hour.
Why is green such a prominent color in Hero Mode? In one of the Sunken Scrolls, it shows that the Original Squidbeak Splatoon had green tentacles.
If you talk to Cap'n Cuttlefish in the Single Player hub, he'll sometimes comment that he produces less ink than he used to. This explains why Cap'n is so short and skinny compared to the younger Inklings. He doesn't make as much ink, so he doesn't have as much mass as the younger squids.
It would also explain why he's so much smaller compared to pictures of him that you find in Sunken Scrolls.
The Rainmaker weapon might be named for its ability to rain a large amount of ink on the field without needing to be refilled, but another subtle detail is noticed when firing it: it leaves patches of ink on the ground, in the shape of rain drops.
The fact that the final time you send Octavio's large bomb back at him knocks him clean out of his ship. The first three times, the guy's got himself under control and is continually working the CDs. However, after the fourth time, Agents 1 and 2 override his music and put on some of their own. At this point, Capt. Cuttlefish and Octavio both start jazzing out and hopping to the beat. When you knock Octavio's ship for a loop at this point, he gets knocked flying out of it. This is because he doesn't have himself suckered into place on the ship. He's got his tentacles up in the air. The music actually helped make him more vulnerable.
The Splattershot line of progression (Jr., Normal, Pro) reflects the evolution of water guns during the early to mid 90's, and their specs reflect this. The Jr is based on old squirt guns that squirt low amounts of water per shot and commonly had clear bodies, and the Jr has short range and low power but can fire for a long time due to the low ink each shot has. The regular Splattershot is based on the Super Soaker 50, one of the first pressure pump water guns and the standard gun of the line, as such being the Jackof All Stats. Finally, the Pro is based on the Super Soaker CPS-2000, one of the most powerful water guns ever made thanks to its water bladder CPS system, but the same system also made it slow to repump between shots and used up a lot of water in a matter of seconds, thus the Pro has higher damage, but lower fire rate and higher ink consumption.
Some of the gear's main abilities actually make sense:
Helmets like Armor Helmet Replica have Tenacity; while Defence Up would seem to make more sense, somebody wearing a helmet would be able to be more reckless thanks to the protection, which would basically be like going into the fray without help. The same can be said for the Gas Mask.
The Legendary Cap has Damage Up. It's the same hat Capp'n Cuttlefish, a solider, wore in a war.
Lightweight Cap is Swim Speed Up, something that is lightweight would be easier to swim with.
Power Mask has Defence Up, considering it's a protective mask.
Samurai Helmet has Strength Up, the Samurai Shoes have Special Duration Up, and the Samurai Jacket has Special Charge Up. All of which involve the use of a weapon and a special weapon. Samurais are known as Warriors (Main) and Protectors (Special).
The Splash Goggles have Defence Up: They're designed for Protection.
Octoling Items are Bomb-based and Special-Based: In Japan, bombs are widely considered to be "evil". We have Bomb Range (Goggles) and Ink Saver Sub (Armor), and one of the Specials is a missile (Boots). Guess what one of the enemies in the main campaign are.
Octo Tee and Forge Octarian Jacket have Haunt, much like how Octarians haunted Inkopolis.
The Navy Items have Damage Up, What do Navies often do?
While not the proper boot type, the Blue Moto Boots have Ink Resist Up; boots are often protective from dirty and messy things.
You'd think that Stealth Goggles should have Stealth Jump or Stealth Swim, but Swim Speed Upwould allow a great getaway and recon.
The Pilot Goggles have Bomb Range/Sub Power Up, which makes sense in both cases Bomb Range because pilots are naturally going to be fighting from a distance, and Sub Power because they need to use weapons tactically (and also because Bomb Range was lumped into Sub Power).
The names of the Squid Sisters' songs:
Ink Me Up is actually a creative way of daring someone to fight. The song is essentially called "Come at Me Bro."
City of Color: The Sisters grew up in Calamari County. This is their impression of Inkopolis.
Marie's solo, Tide Goes Out: Marie makes many comments about the backgrounds of stages, which is often water. Clearly she likes water.
Maritime Memory may have the same meaning.
Fresh Start: STAY FRESH!
Calamari Inkantation has several meanings:
They may have named it after Calamari County. In a way, it could be a shout-out to their homeland.
It's said the song works as kind of a counter-spell: The name is basically "Squid Spell."
Alternatively, its name comes from their names. In other words, "Our Spell."
The fossil of a human with a Wii U becomes horrifying the more you think about it. What would've or could've happened to cause the person to become a fossil in the middle of such a casual activity?
Apparently the end of the world came before the Switch could be released.
What makes this extra strange is the Wii Remote tied to a Pro Controller. This was recommended by Splatoon's official Tumblr page as a way of allowing the second player to use motion controls in the Battle Dojo. This set-up has never been used for any game other than Splatoon. Does that mean Splatoon existed within its own universe?
No, wait a minute... where the hell are the whales? If the oceans changed drastically due to environmental calamity, did the whales also... oh god!
Many elements have drawings of whales and dolphins, like the notice board in Inkopolis and one of the variations of the Nozzlenose, so it seems like our cetacean friends are doing just fine.
lending more credence to that supposition, Marina mentions during the Unicorn vs. Narwhal Splatfest that her landlord is a narwhal. Narwhals are basically whales with giant protruding tusks.
Imagine hero mode from the viewpoint of the Octarians. You have lived your entire life underground, as have all of your kind for a hundred years. Your civilization is literally crumbling, but you would be able to make do if only you had a little more electrical power to use. The surface is dominated by the inklings, who know nothing of rationing or shortages. They could easily spare some of their zapfish for you if they wanted. Compared to your people, they are hedonistic and lazy. So you build up an army, bolster it with powerful machines, and launch surprise raids to acquire the resources you need to survive. Every factor is working to your advantage. Then you lose completely and utterly. And if you could not win under these circumstances, you cannot ever win. Your people's situation used to be bad. Now it is hopeless.
Furthermore, in Hero Mode, after defeating the boss of each Dome, if you stick around before collecting the Zapfish, you'll eventually hear some unsettling loud noises. If that was the sound of the Octarian habitat domes collapsing from power loss, then that means that their situation got worse immediately after Captain Cuttlefish sent Agent 3 to reclaim Zapfishes.
When you die in Splatoon, you explode into the opposing team's colour ink. Does this mean that the inklings are using each other's blood as ammo?
When you really think about what's happening, you're basically making other inklings explode by forcing foreign ink into their body, which is displacing the inkling's own ink to a point where the body can't keep itself together anymore.
Between the value the storekeepers and newscasters place on "freshness", and the newscasters dressing up like cut and cooked squid, is it possible the inklings have a racial memory of being food and are now making a virtue out of it? (Or non-racial: what does Judd eat, and how important has Judd become to their society?)
You can see unevolved fish in the water in various stages (Arowana Mall, Bluefin Depot). Not to mention Squids are carnivorous (and Callie and Marie mention eating Catfish Burgers and Hot Dogfish), so it's unlikely they hold his carnivorous tendencies against him.
It probably also extends to the other species, or at least for shrimp as Crusty Sean dresses up like tempura.
Being composed of ink, the inklings dissociate in water. So why are some Inklings supporting water slides in the second North American Splatfest?
It might be considered an extremely scary ride in-universe, which is why it is compared to roller coasters. There's one of two ways this could be implemented:
Inklings actually dissociate at the watery bottom, then respawn at a spawn point at the top of the water slide. (Considering the average teen engages in turf wars and gets splatted once in a while, they might not mind it.)
The water slide doesn't end in a deep pool of water at the end, so nobody "drowns" at the bottom.
The fact inklings dissolve in water makes their world a lot more scary seeming. Realistically, inklings should die when they dissolve, though since a Game Over when falling into water doesn't make for a fun game, they simply respawn. What must rain and snow do to them? There's also the issue of masses of water being lethal to inklings. The implications they live in Japan, which are a series of islands surrounded by water, only makes it worse.
Respawning is actually a thing Inklings and Octarians are capable of doing in-universe, so falling in water is just an inconvenience to them. No species that died for good the instant it came into contact with water would have any business becoming such a major part of the world.
Not exactly a 'horror', but still mildly off-putting. Apparently at least some other species still eat salted squid. Wouldn't that be a bit creepy to inklings. considering they're evolved squids?
About as much as a human eating an ape.
So pretty high on the iffy scale, at least in America.
But, yknow, if youre really hungry...
Did the ecological disaster that hit the planet completely stop all weather patterns? You'd think that with Inklings dissolving in water, a sudden rainstorm or blizzard would prove horrifying to their society.