Here is the full list of all 14 ALONE? achievements.
Find and Unlock Ending 1
Find and Unlock Ending 4
Read All Notes
Find and Collect the Car Keys
Enter the Morgue
Enter the Sewer
Replace 3 Piano Keys
Unlock the Safe
Return the Jesus Statue
Find and Unlock Ending 2
Find and Unlock Ending 3
Collect all Screws
Enter the Basement
Find and Collect the Flashlight