This "mod" is my save file from the game. I have actually managed to get this achievement on my first playthrough so I guess it isn't that hard? But you could miss some character and you would had to replay quite a lot of the game.

Where should I put the save?

C:\Users\YOURUSERNAME\Saved Games\Beyond Two Souls Steam\Save

Okay, save is placed. How do I get the achievement?

You need to replay final mission, you can easily chose missions from main menu.

Why are you just giving away your save file?

Look at my Nexus profile, this isn't first game I have put save files on nexus.

Link to download the "mod"

https://www.nexusmods.com/beyondtwosouls/mods/2

*Don't forget my comment section isn't democracy. In the past few people expressed themselves in negative way about my save files - If you don't like this save file because "others should work for it" - your comment will be deleted.