Here is the full list of all 16 In Between achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Complete all levels
Find the 5 hidden glimmers of hope.
Reach all MindImages
There's more than one route to follow.
Watch the credits
Complete Acceptance
Complete five acceptance loops
Complete Depression
Complete Bargaining
Complete Anger
Die 100 times
Complete Denial
Do a successful gravityzone jump
Complete Tutorial
Reach one MindImage
Complete the game without dying