Here is the full list of all 20 The MISSING: JJ Macfield and the Island of Memories achievements.
Select Continue after the ending and start a new run.
Read all of F.K.'s hidden texts after finishing the game.
Acquire every donut.
Find every Sleepy.
Read all of the texts from the past.
Don't get too addicted to your phone.
Crane operation is dangerous work.
Read a hidden text from F.K. after finishing the game.
Complete the game.
Reach the top of the clock tower.
Escape danger.
Fall off a bridge.
Get run over by a train.
Escape from something scary.
Jump over that black thing!
Find the first Sleepy.
Chat with F.K. for the first time.
Let the strange deer empower you.
First, you need to find Emily.
Awaken at the campground.