Update (21.10.2019):

The game was remastered and some new content with 3 new achievements was added.
The new achievements are only available in the "Dig out" route.

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Feel free to tell me if i made any mistake, i was making this guide right after i finished all the achievements myself but i could remember something wrong.

I saw no guide here with all achievements in one place so i decided to make one.

(At least not one in english, after i made this guide i saw the russian guide has achievements in it but i didn't try to read it yet)

This guide is simply combined from what i found in my own playthrough and what i found on the forums here when i looked how to do the missing achievements myself.

It's not possible to get all achievements in one playthrough of the chapter as there are routes that exclude each other (saves help though).
You can use the "ctrl" key to speed up dialogues you already saw before.

Also, spoilers, play the game at least once before reading this guide.

(Missable)
Look at the Antiquity poster on the board at the camp.


(Missable)
Read the letter you find on the chair in the camp, and then lie twice to Vander that you didn't when you give it to him.


(Missable)
Eavesdrop the girls in the water until they notice you.

Experimenter I thought it might work!

(Missable)
Try to combine cookies with a shovel.(deleted)


(Missable)
Give cookies to 3 of them: Vander, Lazy, Serban, Bo or Flynn.

To get the cookies you need to talk to Roui's mom at the cafe right after the route choice. Pick the answers at the top.

(can someone confirm Bo works for achievement? personally i used Vander, Lazy and Serban)
Thank you Proh0r for confirmation and Monster BOT for adding Flynn!


(Missable)
Near the end of the chapter, pick to have a photo with Bo and Flynn.

In the game there are routes that exclude themselves.

At the point of the game when you have to get rid of the plant there is a choice that define the route:

• Dig out
  
  There is one choice that will affect if you can do the DLC plot:
  • Getting people out of the water by stealing the whistle
    
  • Getting people out of the water by asking Alek (this one allows you to do it)
  
  
• Cut down
  
  Depending on your relations with Vander, this choice will put you in one of these routes:
  • The Sedative Route - if you get the amulet from him (good relations).
    
  • The Wine Route - if you get the strawberry syrup from him (bad relations).
  
  
  Example dialogue options to get The Sedative Route:
  • Don't worry, Brilla will not do anything.
    
  • So it's a predator?
    
  • Well, okay... let's say it's... hm, the Mad Rook.
  Example dialogue options to get The Wine Route:
  • She'll kill you
    
  • Keep an eye on what you're planting in your Greenhouse.
    
  • Grow up and stop believing in fairy tales.

You get it for picking to dig out the plant instead of cutting it.


(Missable in that route - a choice)
Talk with Alek the to get people out of the water.


(Missable in that route - a choice)
Steal the whistle instead of talking to Alek.


(Missable in that route - a dialogue choice)
When talking to the Veglamb, pick to take a feather.


(Missable in that route - a dialogue choice)
When talking to the Veglamb, pick the meat.

"The DLC" Achievements (Missable in that route):

To be able to start the DLC quest you need to ask Alek to get people out of the water instead of stealing the whistle. Next thing to do is to view the note at Rasko's wagon. If you need more help look at the guide. (link at the end of this section)


(Missable in that route - a dialogue choice)
When talking with Brilla about "The old man and wooden horses" pick "He sacrifices them for his own purposes"


(Missable in that route - a dialogue choice)
When prompted with a choice while talking to Grullo, pick "Write a letter to the Scientists"


(Missable in that route - a dialogue choice)
When prompted with a choice while talking to Grullo, pick "Suggest help", then go talk with Candy

If you're having troubles with the DLC, a more detailed guide to the quest itself can be found here:
https://steamproxy.net/sharedfiles/filedetails/?id=1895954148

Take the axe.


(Sedative route only)
Cut the wire supporting the plant in the Greenhouse.


(Wine route only)
Make the electricity work in the room next to the Greenhouse.


(Sedative route only)
Use the dart on Brilla.


(Wine route only)
Give the wine to Brilla.


(Missable in that route - a dialogue choice)
Refuse to go with Flynn.

Walkthrough for chapter one:
https://steamproxy.net/sharedfiles/filedetails/?id=2469643076
Guide for the Immortal Horses add-on side-quest:
https://steamproxy.net/sharedfiles/filedetails/?id=1895954148
Walkthrough for the 2nd chapter:
https://steamproxy.net/sharedfiles/filedetails/?id=2444024861
Achievements guide for the 2nd chapter:
https://steamproxy.net/sharedfiles/filedetails/?id=2444062225