To get this achievement you have to have all characters killed.
This save file also gives possibility to get "All endings.." achievement since you need to have characters dead to get half of those endings and I actually got the achievement so maybe you are able to get it as well? No idea how it works in this game and no way for me to test it again.
What to do with save file?
Unzip file and place save file here:
C:\Users\YOURUSERNAME\Saved Games\Beyond Two Souls Steam\Save
This save file also gives possibility to get "All endings.." achievement since you need to have characters dead to get half of those endings and I actually got the achievement so maybe you are able to get it as well? No idea how it works in this game and no way for me to test it again.
What to do with save file?
Unzip file and place save file here:
C:\Users\YOURUSERNAME\Saved Games\Beyond Two Souls Steam\Save