In Astral Chain you will be given Files to complete which works as chapters in the game, the game has in total 11 Files for you to unlock and play through in the main storyline but there is a File 12 which the developers have hidden in Astral Chain and this guide will show you how to unlock File 12 (Epilogue) in Astral Chain.
How to Unlock File 12 (Epilogue) in Astral Chain
In each File, there is a story content which you will have to complete to move on to the next one, but after you complete all there 11 Files there is one more hidden in the game for the players to get some post-completion gameplay.
To unlock File 12, you will first have to complete all the files from 1 to 11 and beat the entire game, after the credit roll, you will get the chance to save the data again over the existing file.
After doing that head over to the main menu and load the file again, once you do this you will get a bit of epilogue story and you will find yourself back in Neuron HQ.
Once there your main goal is to complete the missions given by Olive, which will help you clean the corruption around the Ark.
The missions will have a limited amount of items and you will have to complete within the given parameters. This is a post-game content which is an added bit of extra gameplay for players who complete the game.
This is all there is to know about how to unlock File 12 in Astral Chain.