First of all, this guide contains heavy spoilers! I'll basically spoil everything.
As such, I highly recommend you to play the game once without the use of this guide.

Difficulty doesn't matter
You may as well play on the easiest difficulty, a.k.a. "Playing video games occassionally".

The achievements in this game do NOT unlock right away!
They only unlock on loading screens, which only appear, if the next chapter of the game has a different playable character than the current one, OR by going back to the main menu and choosing "Continue", which loads the latest save.
For example: You'll have to meet the requirements for the "Happy Birthday" achievement in the very first chapter, but it'll only unlock / pop up upon loading chapter 4, since chapter 1 to 3 are all played through Ethan Mars.

Regarding the mutually exclusive achievements:
There are several mutually exclusive achievements in the game. Always opt to unlock them in the order given in the guide! A few choices don't impact the game beyond the current chapter, but most do!

Some of the achievements have multi-chapter requirements!
One of them will unlock at the very very end of the game, but requires you to do something missable all the way back in chapter 10. Sadly, reloading the specific chapters doesn't work. It only counts, if you replay every single chapter, starting from the chapter you want to reload...
In other words: Follow this guide thoroughly!

I highly recommend to use a controller for this game.

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• Go downstairs to your office and completely finish the drawing of the house, up until Ethan signs it. This requires multiple interactions.
  
• Once asked to, prepare the table for dinner by grabbing and placing the dishes from the cupboard.
  
• Go outside and continuously play with your kids, until the game forcibly stops you to do so.

People had varied levels of success in unlocking the achievement, claiming that the unlock condition is based on whether or not Ethan won against his kids or let them win. If you struggle to get the achievement, try both.

Other tips from the comments:
Suggested by Noks:

It's not about to win or lose against Jason, it's about to pick in thoughts-options the phrase "I think, I go outside and play with the kids". This option appears after preparing table for dinner.

Suggested by Cjcomplex:

When playing with Shaun, stay as far away from Jason as possible. It appears the playtime with Shaun ends early on its own the moment you get close to Jason to start the swordfighting sequence.

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This achievement is supposed to unlock automatically upon the title drop during the cutscene between chapters 02 and 03.
(A handful of people in the comments reported this achievement to be bugged though. Sadly, I neither know what's causing this, nor do I know a fix, if this shouldn't unlock for you. Sorry.)



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Sticking to the schedule is pretty straight-forward.
Make sure to check Shaun's homework, once he's done. Thanks to neji_genius for pointing this out as a requirement.
When in bed, Shaun will ask for his teddy. Grab it downstairs from the washing machine and give it to him for the "good mood" part.



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When talking to Lauren, select: "Compassionate" -> "Convince" -> "Trick".


Self-explanatory:



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You need to interact with all the clues via your ARI:

• Inside the tent: boy's face, orchid on chest, origami in hand, hand second time, cut on leg
  
• Pollen trail near tent, leading to:
  
• Train tracks: blood stain, footprints
  
• Blood on fence
  
• Uphill: footprints, tire tracks

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Nothing achievement related


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Self-explanatory:



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Nothing achievement related


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Norman's part:
Nothing achievement related

Ethan's part:
The time was 4:15 and Shaun was wearing a beige jacket & green trousers.



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Let the robber detect you. Keep your hands up in the air at all times. Pausing the game will actually automatically result in a failure.
Now, choose the following conversation options:

• Calm
  
• Name
  
• Reason
  
• Help
  
• Killer?
  
• Drop Weapon

After you've unlocked the achievement above, return to the main menu, select "Chapters", reload the chapter and choose to "Save" progress!

Do nothing until the robber has pulled the trigger and fled the scene. Talk to Hassan.

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Nothing achievement related


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Take the back door and follow the path from there, without the journalists approaching you too much.



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Time will stop for anyone but Ethan for a while. During that part, hit 50 people.


Go to the end of the hallway and then left twice to end up at row 18. Use the upper interaction for locker 3.



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Nothing achievement related


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Nothing achievement related

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This chapter has 2 mutually exclusive achievements:

It's easy to choose which achievement you want to unlock:

• Want to shoot him? - Pull the trigger.
  
• Don't want to shoot him? - Literally do nothing. Norman will choose the correct dialogue options himself.
  
  • (At least he did on easiest difficulty.)

After you've completed the chapter the first time, go back to the main menu, choose Chapter select and replay the chapter. Doesn't matter which achievement you continue the game with.



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Pretty straight-forward.
Change the diaper, heat up the bottle, feed the baby and then put her to sleep, without making mistakes.



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Even if you're presented with several choices as to go left OR right, you actually need to pick the specific order listed below.

Note, that the instructions below were written for the use of a PS4-Controller.
While the directions should stay the same regardless of your controlling input, you'll need to replace [L2], [R2], [X] and [O] with whatever is shown on your screen.

The important & achievement related decisions are written in Bold with a preceding Choose.
All the other commands are just to make it easier to keep track of where you are in the command chain.
The button prompts - L2/R2 - refer to the hardest difficulty. On the lowest, they're replace with [X] and [O].

Here you go:

• Choose left
  
  • Go right
• Choose right
  
• Choose left
  
  • Go left
    
  • Go right
    
  • Car is going wild, repeatedly switch between left and right.
    
  • Go left
    
  • Go right
• Choose left
  
  • [R2] <---- depends on your difficulty
    
  • Go right
    
  • Go left
    
  • Go right
    
  • Go left
    
  • [L2] <---- depends on your difficulty
• Choose right
  
• Choose right
  
  • Go left
• Choose right
  
  • A police car will ride up to your left. You need to steer away, without hitting the police car.
    
  • [R2] <---- depends on your difficulty
    
  • Go right
• Go left or right (doesn't matter).
  
  • The following QTE's don't make a difference anymore.

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Nothing achievement related


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Self-explanatory:

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Nothing achievement related


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Self-explanatory:



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Slowly move through the tunnel while following the direction the flame is pointing towards. Once you're through, leave through the Coward door.




After you've unlocked the achievement above, return to the main menu, select "Chapters", reload the chapter and choose to Save!

Proceed as before, but don't go through the Coward door this time.
Follow the path illustrated on the right.







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Nothing achievement related


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Nothing achievement related

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This chapter has 2 mutually exclusive achievements.

Both are self-explanatory.

After you've completed the chapter the first time, go back to the main menu, choose Chapter select and replay the chapter.
Doesn't matter which achievement you continue the game with.



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Nothing achievement related


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This chapter has 2 mutually exclusive achievements:

Regarding Goldfinger:

• Grab the axe in the corner of the room.
  
• Grab the metal bar next to the table and heat it on the stove until it glows.
  
• Grab the disinfectant in the bathroom, or the alcohol in the kitchen.
  
• "Do it".
  
• Apply the disinfectants or cauterizers.

After you've completed the chapter the first time, go back to the main menu, choose Chapter select and replay the chapter.
Doesn't matter which achievement you continue the game with.



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Uncover the window by removing the wood in front of it. Push the red box towards the window and have Ethan climb out of it.
Move away from the camera towards the busier street and zig zag through the cars.
Go down to the subway and cross the train tracks to board one of the subways.


Continue to the next chapter for now, but note, that we'll reload this chapter in a few minutes!


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Self-explanatory:


Go straight to the bathroom and take a shower, instead of taking the Triptocaine.


After these two, go back to the main menu, select "Chapters" and reload chapter 29) Fugitive.
Make sure to select to "Save" progress and replay both chapters 29 and 30!


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Self-explanatory:



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You NEED to replay this chapter with Ethan arrested in the last!

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Self-explanatory:


It's important for some of the endings, that you keep playing with the arrested route!


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Don't interact with anything you don't have to and go straight to Manfred.
You'll have to clean:

• The white phone in the back.
  
• The black phone on the desk.
  
• The two shot glasses, the bottle and the magnifying glass.
  
• The ballerina on the center glass case.
  
• The front door.

If you've missed something, the camera will point it out after you've left the scene.
If that happens, return to the main menu, select "Chapters", reload the chapter and choose to Save!



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This chapter has 2 mutually exclusive achievements:

Do not kill the drug dealer. Instead, put the gun away.


After you've unlocked the achievement above, return to the main menu, select "Chapters", reload the chapter and choose to Save!

This time, shoot the drug dealer.



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Do NOT accept the offered drink. A littler bit later, if he asks "You are not drinking?", answer "No"!


Pretty self-explanatory. Get you right leg free first, then the left, and continue from there.


Make sure, that Madison survives this chapter!



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Find all clues with ARI. The acid bath in the southwestern corner will advance the chapter, so check it last.

• Three sets of blood trails that lead to the acid bath
  
• Mugs in Mad Jack's office
  
• Size 10 footprints
  
• Tire tracks that match the Origami Killer's
  
• A pollen trail in the back
  
• Spilled paint, nearby the pollen trail.
  
• The acid bath.

Fight Mad Jack until you get the chance to "Impress". Once again, resist the triptocaine and engage in the second part of the fight.


Written by Caspian Roach in the comments:

A clarification for 35) Goodbye Mad Jack - Survive Mad Jack fights: you need to specifically FAIL the QTE after you have the Mad Jack at gunpoint, when everything goes blurry. This isn't an instant fail state, it unlocks the second fight that you also need to win to unlock the achievement.

I kept completing that QTE and couldn't figure out what I was doing wrong. If you end up arresting Mad Jack, you did it wrong and need to restart from the checkpoint or the chapter. The successful achievement run does not end up in Mad Jack's arrest.

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Pretty self-explanatory.
Keep the flame until Scott comments about the eggs looking ready, then serve them on a plate.



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Nothing achievement related


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Self-explanatory, but potentially very annoying:



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Nothing achievement related


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During the striptease, only unbutton your shirt and nothing else.

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Another chapter of collecting all clues with ARI.

• Orchid pollen on the desk
  
• The scattered papers on the floor
  
• The gasoline tickets
  
• the bullet shells near the door
  
• The gun in the corner
  
• Paco's body
  
• The gun in the center of the room
  
• The lamp Madison used.

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Kiss Madison and forgive her.


As Madison, call room number 207 to warn Ethan.
As Ethan, choose to escape by climbing onto the roof.



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Let Lauren die.
Successfully escape the car, by your own inputs! If Scott escaped by himself after some time, restart and try again, otherwise it may not count towards the achievement progression.



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Not getting shot is self-explanatory.
When Kramer has a heart attack, just select to "Leave".



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Nothing achievement related

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Drink the poison.


After you've unlocked the 2 achievements above, return to the main menu, select "Chapters", reload the chapter and choose to Save!

Do not drink the poison. Choose "852 Theodore Roosevelt ROAD" from the options given.



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• Analyse Blue Lagoon video
  
• Analyze the Gun
  
• Geoanalyze the gas receipts
  
• Geoanalyze "The killer is or was a cop"
  
  
• It's NOT Blake! Do NOT accuse him!

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Will be skipped for now, since we let Lauren die.


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Nothing achievement related


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Nothing achievement related

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Let Madison die.



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As Norman, fight Scott until he's about to fall to his death. Rescue him.
After that, just stop doing anything, since we need Jayden to die afterwards.


As Ethan, save Shaun.


This will unlock the endings:

• News Report
  
• A New Start
  
• Dead Heroine
  
• Uploaded
  
• Unpunished

And with that, onto the clean-up:

At this point, we're still a few achievements and several endings short of 100%.
You will have to re-enter the story at several different points and play them through to the end.
Make sure to choose "Save" progress, whenever you load a chapter from the main menu!

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Restart at chapter 51) Killer's Place.

Enter the password "Max" to get the warehouse adress from the computer. Survive the fire by making your way to the kitchen and climbing in the fridge.


After that, in chapter 52) The Old Warehouse:

• Madison needs to escape the police, in order to warn Ethan.
  
• Jayden needs to kill Scott.
  
• Ethan needs to save Shaun

This will unlock the endings:

• A New Life
  
• Origami's Grave
  
• Case Closed

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Restart at chapter 52) The Old Warehouse:

Literally do nothing as Norman and Madison.
Madison will get arrested, Jayden will get killed by Scott and Ethan will be shot by the Police.


This will unlock the ending:

• Ethan's Grave

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Restart at chapter 46) The Rat:
Do not drink the poison and choose the wrong adress (Lane or Park -- DON'T pick Road)
In chapter 47) Solving the Puzzle: Close ARI and choose to give up
In chapter 51) Killer's Place: Let Madison die, for example. by jumping out of the window

This will unlock the endings:

• Origami Blues
  
• Smoking Mirror

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Restart at chapter 51) Killer's Place:

Successfully escape, but without the correct adress.

This will unlock the ending:

• Tears In The Rain

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Restart at chapter 42) On the Loose:

Kiss Madison, but don't forgive Madison.
Let the police arrest Ethan.


In chapter 43) Trapped:
Untie yourself, then interact with Lauren to free her, then break the window to escape.


In chapter 44) Face to Face:
Self-explanatory:


In chapter 47) Solving the puzzle: Give up
In chapter 51) Killer's Place: Escape, but without the adress.

This will unlock the endings:

• Helpless
  
• Square One
  
• A Mother's Revenge

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Restart at chapter 51) Killer's Place:
Find the adress and escape, but don't call anyone.

In chapter 52) The Old Warehouse, save Shaun as Madison and survive the fight with Scott.

This will unlock the endings:

• Innocent
  
• Heroine
  
• Resignation

And as such: