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
Truth Revealed
Missing Journalist
Case Unsolved
All Letters Found
All Keys Found
Bloody Knife
Derrick Tyler's Story
Matthew Brooks' Story
Steve Moss' Story
Dying Man's Letter
Dorothy Patterson's Story
Bernard Hopkin's Story
Charles Roberts' Story
Best Friends Forever
All Tools Found
Oliver Gibson's Story
Wanda Tyler's Story
Sofia Miller's Story
All Newspaper Articles Found
Here Lies Sofia
Scott Brooks' Story
Scott's Secrets
The Hidden Truth
Vivian Roberts' Story
Trisha Roberts' Story
The Secret Lies With Her
Mary Martinez's Story
Andrew Reed's Story
Guest's Lost Cap
Tutorial Completed
James Howard's Story
You're Fired