Here is the full list of all 43 What Lies in the Multiverse achievements.
Complete the Prologue
Complete Chapter 1
Complete Chapter 2
Complete Chapter 3
Complete Chapter 4
Complete Chapter 5
Complete Chapter 6
Complete Chapter 7
Complete Chapter 8
Finish the game
Die by falling from a long distance
Get crushed by a box
Die by drowning
Get shot by the bartender
Die by jumping off the train
Get crushed by a sliding door
Get pulled away by the river's current
Die by poisoning
Die by been hit by a laser
Die by falling up into the sky
Die in every possible way
Sit in Heis' lap
Fully listen to the grandma's story.
Listen to all dialogs with Everett at the campfire
Complete the optional puzzle.
Wait for Everett at the casino
"Finish" Barres' play.
Watch how Erwin is doing by themselves.
Meet the goose
Use Everett's voyager by yourself
Read all Everett's diary
Read all Ez's logs
Watch all the recordings in Everett's studio
Get trapped inside a wall.
Get dizzy by switching universes too fast.
Find your first memory.
Break 15 pickable boxes.
Succeed at one QTE
Succeed at both QTE
Sit in all benches
Find all the hidden memories.
Watch the alternative ending
Get all the achievements