On this page of the guide to Deathloop, you will find the exact information on how the game is saved. You will find out whether you can manually save the game state, when the game saves automatically and when you can safely turn off the game. This knowledge can save you from losing your progress and having to repeat part of the game.
In Deathloop, there are automatic saves, and they are created in three types of situations:
1) Entering the new district - Autosave is created when you use the entrance to the district and start a new mission.
2) Completing the expedition/mission and returning to the preparation screen - The game creates an automatic save of the game status when the summary screen from the last expedition displays. In addition, separate autosaves can be created each time you change the loadout of the character.
3) Death of the character and the end of the loop - The game saves the "final" defeat. It will be necessary to start a new loop, and all the items and powers that were not previously purchased for Residuum will disappear from the inventory.
Deathloop does not have the option to save the game manually. You have to be aware of this throughout the game. We advise you to avoid risky actions that can expose the character to lethal danger. In the game, there is an option to use the power of Reprise, which allows you to resurrect yourself after death without ending the loop, but it is possible for a limited number of times.
If you want to turn off the game safely without the risk of losing the last progress, you can use the option to return to the main menu in the expedition preparation window or just after loading one of the districts.
If you close the game during exploration, that is, before returning to the channels and the preparation window, you can lose progress from the last autosave. After restarting the game, it may be necessary to explore the recently visited area from the starting point.