Here is the full list of all 20 One Step After Fall achievements.
Collect the first letter fragment.
You found Cameron’s Photography.
Scare the crows
Collect the book The Sea of Thieves
Collect the book The Ghost in Silence
Collect the book Carol's Depression
Collect the self-help book “Another achievement in your life”
Collect the book Green Lights Under the Sky
Meet the Scarecrow
Die once
Collect the No Cartoon 4 Zombies Action Figure #8
Collect the No Cartoon 4 Zombies Action Figure #5
You found the M1911.
Inspect the wine bottle
Turn on the radio
Inspect the medicine bottle
Inspect Tera Solutions polaroid paper pack
Find the chicken man
Achieve the False Ending
Achieve the Real Ending