Here is the full list of all 15 If Found... achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
(That we may live to see this time next year.) Write every diary entry in Opening.
Erase for the length of one Mass.
Finish ‘The Back of Beyond’ chapter.
Choose the Mayo flag in the character creator.
Finish ‘Opening’ chapter.
Choose the transgender pride flag.
Finish ‘The Anomaly’ chapter.
Finish ‘Cassiopeia was over Keel’ chapter.
Finish ‘Coming and Going’ chapter.
(Do you understand?) Read an Irish annotation.
Draw for the first time.
After finishing the first chapter, go to the last chapter.
Play the game in Irish.
Find Colum drinking coffee.
Erase for the first time.