Headscratchers / Endless Ocean

• In both games, the abyss starts at about 80 metres. Wait, What?
  • That's the entrance to the abyss. It's implied the "boring" swim down to the abyssal zone is bypassed during the loading sequence between the abyss and its topside entrance hole.
• How did the Okeanos sink their temples?
  • A Wizard Did It. Or maybe A Whale Did It, considering they have a song that drives whales nuts and makes them start smashing things: they just directed them to smash out the supports under the temple (no one said they weren't originally on piers or something).
  • How did the Singing Dragons maintain a breeding population with such a small number of animals? How did they eat and go up for air if the temple is buried underwater? Also, how would the Okeanos Guardian survive for so long?
    • The Dragons might just be very long-lived whales, much like the Bowhead Whale.
    • A theory was proposed somewhere that there is more to the temple that the player is unable to access, implying there is a section of the temple that 1) is big enough to allow a whole species of whale to breed undiscovered, 2) is well-hidden enough to allow the temple itself to remain undiscovered for literal centuries, and 3) is open to the surface, allowing the Singing Dragons and Commerson's dolphins to resurface.
• How do those tanks in the aquarium allow fresh and saltwater fish to live together?
• How do the dolphins you befriend in the sequel get to the other places around the world, Gatama Atoll aside? Are they swimming all the way there and following the plane? Or are they plane cargo?
  • Pokéballs.
• In Blue World, how do very modern salvageables get deep into places that have been lost and even sealed up for hundreds of years? The Twilight Temple area, I can sort of see, as there's an open area that maybe humans have been discarding things into from above. But the Cavern of the Gods (Zahhab Temple)? Even Valka Castle should have all its modern stuff in a pile at the Well Bottom... and not all the way into the King's Chamber. Or really, anywhere past Spiral Tower.
  • At least in the case of Valka Castle, it might have been the resident false killer whale picking up and playing with the objects.
• How did Valka Castle end up being a mythical place that no one has ever found, when it has a tower sticking right out of the water?
  • During the day, the Ciceros Undines surrounded it completely. Those dispersed during the night, but GG implies that Thanatos coming by then is a normal occurrence, which would likely drive off most divers. Also, the only part of the tower actually exposed is a small well, which most divers would likely overlook in favor of getting away from a giant maneating shark. The rest of the castle may actually be visible somewhere (there are windows looking out into the ocean), but Thanatos can be seen swimming out there, so it's likely considered a very unsafe diving spot, if it's even accessible prior to the discovery (it may be blocked by the Undines as well).
• For a game that likes its Green — or should I say Blue — Aesops, it's sure not giving me a lot of incentive to clean up the ocean floor when some salvageable might — or will — not be valuable enough to pay for its own appraisal. Yes, there's completing the Salvage Book, but that's only profitable as long as the squares for their combinations of materials and type aren't filled. After that, well, you're probably going to just leave those metal-only Small Rings, wood-only Small Books, and so on. In real life, cleaning these things out of there would be rewarding; in-game, they risk slowing your economic ascent.