Fire!
Fired the first flare


Connected
Connect with mirror Kay for the first time


School's out
Made it through school


Moses
Opened a path through water


Sunny
Finished Level 1


Lonely at the top
Reached top of the Skyscraper


Mama and Papa
Finished Level 2


Breakdown
Finished Level 3


Resolve
Finished the game


Runaway
Travelled very far by foot
Just walk

Seeker
Fired 30 flares
You will get it after using 30 flares

Deep Dive
Jumped headfirst into the water from a high point
I got it just by beating the main storyline. But if you missed this achievement, then in chapter 6.1, go up a couple of floors. Jump off and press the B button on the gamepad

Sailor
Travelled a long distance by boat

(the last four are almost related to the story as they can not be missed. No matter how hard you try)

These achievements include those that are not obvious and are not related to the storyline.

Comfy
Respawned on couch in Skyscraper
The achievement is easy to miss. So if you (like me) didn't get it in the main playthrough, then just run Chapter 6.2 and move in the opposite direction
(Note that you need to die as close to the sofas as possible. After respawn, you'll get an achievement)


Raver
Got grabbed by waterhands 10 times
If you (like me) are playing too well :D
and didn't get this achievement in the main playthrough, then just run Chapter 3.2 and jump into the water.


Human Bait
Eaten by Whale 20 times
The same as with the previous one. For hugs with a whale, chapter 1.3 is best suited


Mermaid
Swam a very long distance
Run the epilogue and swim for fun until you get it.

Danger Swimmer
Swam a long distance while Whale was around
Chapter 2.2
Just swim near the gate

Uncorked
Collected your first Message in a bottle


Bottled
Collected all bottles


Shoo!
Shooed your first Seagull


Flock of Seagulls
Shooed all Seagulls

For convenience, everything is divided into chapters
Chapters 9 and 11 do not contain anything collective

14 collectible items

8 collectible items

8 collectible items

16 collectible items

2 collectible items

10 collectible items

9 collectible items

2 collectible items

1 collectible item

1 collectible item

It wasn't that hard, was it? :)
I wanted to write this guide back in December, but I couldn't bring myself to complete the game because I wanted to play other interesting projects. I know that such a guide already exists, but I still wrote my own, since in most of the achievements I describe other ways to get them, and also attach a video. For collectible achievements, I decided to share not a full 30-minute video, but 10 short videos for each chapter. I believe that this is more convenient and each player can work at their own pace, without fear of forgetting where they left off and having to review part of the video again. There will also be no "omg, the video is so long, I won't play this game, as it will take a lot of time."
In any case, use the guide that you like and play at your own pace