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