Here is the full list of all 33 The Painscreek Killings achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Completionist
All Letters Found
Missing Journalist
Truth Revealed
Case Unsolved
All Keys Found
Steve Moss' Story
Charles Roberts' Story
Wanda Tyler's Story
Best Friends Forever
Bloody Knife
Oliver Gibson's Story
All Tools Found
Bernard Hopkin's Story
Sofia Miller's Story
Dorothy Patterson's Story
All Newspaper Articles Found
Dying Man's Letter
Derrick Tyler's Story
Here Lies Sofia
Scott Brooks' Story
Scott's Secrets
Vivian Roberts' Story
The Hidden Truth
Andrew Reed's Story
Matthew Brooks' Story
Trisha Roberts' Story
The Secret Lies With Her
Mary Martinez's Story
Guest's Lost Cap
Tutorial Completed
James Howard's Story
You're Fired