WARNING!!!! THERE WILL BE SOME SPOILERS, SO, BE CAREFUL...
This is my first guide. English is not my first language, so, don't be so rude. Only trying to help.

Since there is no guide for the achievements, i thought i could give more information about the achievements, so, unlocking them will be easy. This guide is for people that already finished the game and want to unlock all achievements.

So, let's begin:

Finished prologue
Play the prologue of the game and finish it, then you will get this...

Kill the pig
Kill the sow in order to get this...



The sow is a mutated big pig located in the pig shed [Silent forest], in order to kill him, you will need to follow this steps:

• Go to Piotrek house and buy a cable. (you will need to kill a dog in his garage in order to talk with him)
  
• Go to the pig shed.
  
• Find a small building located in the pig shed with a generator and a breaker panel
  
• Fix the cable.
  
• Turn on the generator.
  
• Go to the breaker panel, read the note, remove the lock.
  
• Pull the level all way down.
  
• The sow is now dead.

Note: you can also kill the sow with ranged weapons or a molotov. If you choose to kill with this method, the pigs will become hostile, so be carefull.

Warning: This have severe consequences in the story, but in order to get this achievement you will need to kill the sow.

Sleep in the grave
Lie in the grave (Dream sequence: The grave).


Note: You will reach to this dream sequence when you reach the dose tier 2 or 3 of skills (in the oven). In the dream sequence follow a path until you see a dead body, a shovel and a grave, click in the grave to rest in them.

Tip: Once you get the achievement, you can press in your keyboard alt + f4 to close the game and get the another achievement: no sleep for the wicked, but be fast because if the dream sequence ends, the game will save and you will have to start a new game to get the another achievement.

No sleep for the wicked
Kill the black chomper (Dream sequence: The grave)


Warning: the black chomper is very fast, if you are killed, press alt + f4 to exit and retry before the dream sequence ends.

Wolf's path
Give the key to chicken lady's locked room to the wolf...


Note: when you give him the key, the wolf will dissapear... you can find him in his hideout full of dogs [old woods], you will need to enter and find him. Then he will escort you to the doctor's house to find some clues about the doctor.

Musician's path
Give the key to chicken lady's locked room to the musician...


Note: When you give him the key, the musician will request a new violin to impress the pretty lady. You will find this violin in the creepy house in old woods, but be careful, in you don't place the letter in his mother inventory, the parents of the musician will transform in chompers.
Once you get the violin, you can find the musician in the silo [Silent Forest], and he will give you some information about the doctor.

Willpower
Survive and escape from the hallucination.


Note: In the musician's path, you will need to find the train wreck in old woods, the metal door is open but nobody is inside, then the door closes and you will see a gas dispersing. Once the doctor drugs you, you will enventually caught in an hallucination. In the hallucination, you will be chased by some chompers, you will need to run and follow a path(opening doors and other stuff) you will see a dead end, at the end just jump to the abyss and you will escape.

Chapter 2
Go to the undergound and open the big metal door with the key you get from the doctor in order to finish the first chapter of the game.

Entertainer
Kill the wolfman in chapter 2.


Requirements: Ignore wolfman request, dont give him the key(chicken lady's locked room). Also don't kill the wolfman in chapter one.

Note: In one day in chapter 2, the wolfman will steal some of your items in your workbench and he will leave a note. In order to retrieve your items, you must travel to the sawmill, once you enter to the sawmill, you will fight with several enemies until the wolfman appears, kill him and retrieve your items. IMPORTANT: You have only one attempt!

Only ashes remain
Burn the talking tree.


Requirements: Finish the elephants request by bringing the boy from mushroom granny, then you will obtain an oxygen tank and you will need to refill the tank with the compressor. The compressor parts are in the junkyard. (you will need a shovel)

Note: There are 2 basements in the village(swamp), one is blocked. So find the other one.

Bliss
In the epilogue, go to your apartment and sleep in your bed.

Burn them all
In the epilogue, you will need to do extra stuff to unlock a secret ending.


The steps are:

1. Search the mailbox for the postcard
2. Grab the jar of mushroom jelly in the Apartment basement and flip the radio channels until it stops
3. On the first floor of the Apartment, try to open the door next to the drunk guy. Walk away and it will open. Walk back to the door and stare at the fetus
4. Go to your apartment, get changed, then move your TV and couch. Examine the roots, then move your rug
5. Get the tool out of your kitchen, then tear up the floor leading into your bedroom
6. Examine your bed, look under it, DO NOT CLICK LEAVE OR YOU WILL SLEEP
7. Move the bed and jump down the hole
8. Make your way to The Being, pull your hand away
9. Talk to the man laying down to the south-west of The Being, and forcefully take his flamethrower
10. Burn them all

Here is a video:

Insatiable hunger
In mushroom glade in chapter 2, eat mushroom granny


Note: In order to get this achievement, you will need to pick a mushroom from her, now do it again and again until the option eat her appears, then eat her and you will unlock this achievement.

Merciful
Spare the talking tree, find the radio tower bunker and survive the Final Dreamscene.


Warning: you only have one attempt to do this because the metal door closes forever and there is no way to open it again, so watch your step.

Trapped villagers
In the quarry, destroy the logs in order to block the entrance to the village with a boulder.


Note: You need to kill the sow in order to the villagers appear in the quarry, otherwise, they will no appear in the quarry.

List for people who helped me to unlock all achievements
GREGi - No sleep for the wicked
the crown calls - Burn them all video

Special Thanks to Acid Wizard Studio for making a Wonderful Game