Here is the full list of all 50 11-11 Memories Retold achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Unlock the forgiven ending
Find all the collectibles
Find all the collectibles from Part III
Unlock the lone avenger ending
Go home to Julia
Unlock the grudge ending
Unlock the betrayal ending
Take a photo of the rifle on Kurt's kitchen wall in "The Pursuit", fire the same gun in "Peace"
Unlock the sacrifice ending
Unlock the peace ending
See all the credits
Complete Part III
Unlock the revenge ending
Choose to go and save Kurt
Listen to Barrett's tearful account of the lives lost under his command
Threaten the soldier three times to learn the truth
Don't collide with any ghosts
Collide with 20 ghosts or more
Take all the apples back to Lucie
Win at card game against the old ladies in the village.
Win all card games
Give some chocolate to a german soldier
Bring all four wood pieces to the oven
Kick the football in the POW camp
Complete Part II
Get out of the church of Passchendaele
Find all the collectibles from Part II
Cut the german communication
Help Daniel in Passchendaele
Cut the gas in Passchendaele
Find all missing boys from your village.
Perform all moves in the Dance sequence
As Lotty, comfort the soldier under the tree
Pull the cart of crosses in the cemetery
Score with the hidden football in Paris
Purr with Lotty
Catch a rat in the tunnels
Find the hidden food stash in the tunnels
Take a picture of Kurt in "The Collapse"
Complete Part I
Finish Vimy battle without dying
Find all the collectibles from Part I
Save Lothar
Do business with Joe
Send two pictures to Julia
Take a picture of Lotty in Vimy trenches
Use one of the lifts on Vimy Ridge
Avoid all the mines
Explore Julia's Room
Use all your photographic film in one chapter