Here is a 100% achievement guide by Zero.
Introduction
Achieving 100% completion is pretty straightforward. With total of 48 achievements. Forty of them are achieved throughout the main story line and are not missable. The next eight are part of the 400 Days (DLC), six of them are not missable, the next two may take couple of playthroughs.
Main Story
Out of the Frying Pan
Complete chapter 1 of episode 1.
Story related, cannot be missed.
Adventures in Babysitting
Complete chapter 2 of episode 1.
Story related, cannot be missed.
In Your Charge
Complete chapter 3 of episode 1.
Story related, cannot be missed.
Rock and a Hard Place
Complete chapter 4 of episode 1.
Story related, cannot be missed.
It’s Just One Bullet
Complete chapter 5 of episode 1.
Story related, cannot be missed.
Hey, Bud
Complete chapter 6 of episode 1.
Story related, cannot be missed.
Two Enter, One Leaves
Complete chapter 7 of episode 1.
Story related, cannot be missed.
Complete Episode 1: A New Day.
Story related, cannot be missed.
Going Hungry
Complete chapter 1 of episode 2.
Story related, cannot be missed.
Conversation Killer
Complete chapter 2 of episode 1.
Story related, cannot be missed.
Thank you for shopping at Save Lots!
Complete chapter 3 of episode 2.
Story related, cannot be missed.
Guess Who’s Coming to Dinner
Complete chapter 4 of episode 2.
Story related, cannot be missed.
Too Much Salt Will Kill You
Complete chapter 5 of episode 2.
Story related, cannot be missed.
Taking Charlotte
Complete chapter 6 of episode 2.
Story related, cannot be missed.
You Fight Like A Dairy Farmer
Complete chapter 7 of episode 2.
Story related, cannot be missed.
It’s Not Stealing If You Need It
Complete Episode 2: “Starved For Help”
Story related, cannot be missed.
Goodbye, She Quietly Says
Complete chapter 1 of episode 3.
Story related, cannot be missed.
Bad Blood
Complete chapter 2 of episode 3.
Story related, cannot be missed.
Hit the Road
Complete chapter 3 of episode 3.
Story related, cannot be missed.
What now?
Complete chapter 4 of episode 3.
Story related, cannot be missed.
Handle It
Complete chapter 5 of episode 3.
Story related, cannot be missed.
Unexpected Delay
Complete chapter 6 of episode 3.
Story related, cannot be missed.
Look Behind You
Complete chapter 7 of episode 3.
Story related, cannot be missed.
Lend Me Your Ears
Completed Episode 3: “Long Road Ahead”
Story related, cannot be missed.
Georgia’s First City
Complete chapter 1 of episode 4.
Story related, cannot be missed.
Down By The River
Complete chapter 2 of episode 4.
Story related, cannot be missed.
Support Group
Complete chapter 3 of episode 4.
Story related, cannot be missed.
Bedside Manor
Complete chapter 4 of episode 4.
Story related, cannot be missed.
Georgia’s Last City
Complete chapter 5 of episode 4.
Story related, cannot be missed.
For Whom The Bell Tolls
Complete chapter 6 of episode 4.
Story related, cannot be missed.
The Morning After
Complete chapter 7 of episode 4.
Story related, cannot be missed.
Penultimate
Completed chapter 8 of episode 4.
Story related, cannot be missed.
Into The Fire
Complete chapter 1 of episode 5.
Story related, cannot be missed.
Twice Shy
Complete chapter 2 of episode 5.
Story related, cannot be missed.
There Ain’t No Way
Complete chapter 3 of episode 5.
Story related, cannot be missed.
Mercy
Complete chapter 4 of episode 5.
Story related, cannot be missed.
The Marsh House
Complete chapter 5 of episode 5.
Story related, cannot be missed.
What’s in the bag?
Complete chapter 6 of episode 5.
Story related, cannot be missed.
Stay Close To Me
Complete chapter 7 of episode 5.
Story related, cannot be missed.
What Remains
Complete chapter 8 of episode 5.
Story related, cannot be missed.
400 Days (DLC)
Completed Vince’s Chapter.
Story related, cannot be missed.
Abandoner
Completed Wyatt’s Chapter.
Story related, cannot be missed.
Friends Like These
Completed Russell’s Chapter.
Story related, cannot be missed.
Who Goes There?
Completed Bonnie’s Chapter.
Story related, cannot be missed.
Paradise Lost
Completed Shel’s Chapter.
Story related, cannot be missed.
Loose Ends
Completed the Epilogue.
Story related, cannot be missed.
Reunited
Found an old friend.
At the very beginning of Russell’s chapter you are walking down a road. When a car comes you are given two options: Stand your ground or Hide. Choose Hide. Russell then dives in the bushes, and laying there next to you in the grass is the remains of someone you killed off in the game previously.
Two out of Three
Won a game of Rock/Paper/Scissors.
This achievement is earned during Wyatt’s chapter of the game. A few minutes into the chapter your friend will suggest playing rock, paper, scissors to resolve a dispute. Select “Okay, that’s fair” to play. Win best two out of three and the achievement will unlock.What your friend chooses is random, with no reoccurring pattern that I could see. If you lose two, quit to menu before it auto-saves and resume the game to try again. If you’ve already missed this achievement, rewind or start a new game on Wyatt’s chapter. Rewinding will cause you to lose progress you’ve already made, so start a new game on another save slot if you don’t want to lose progress or change the decisions you’ve already made.