This is from
Sensei Neo 's Metro Exodus Windows 10 Hardcore Guide.
Which was based on a comment from
Frankie DrumsNY He referenced an old Xbox version glitch. When I went to the Xbox version guides, similar methods existed but they called for either DLC or uninstalling the game. I thought I would give this a try and it worked.
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Beat the Game
Start a new save in Ranger Hardcore (not new game plus)
Play the first level until the watchmen jumps out and you get an autosave. (You might have to kill another enemy)
Quit to Main Menu
Choose load Game and choose your save slot that has beaten the game.
choose the Dead City save on the next page
Once the loading screen finishes (when arytom finishes talking and press x to play pops up, force quit out of metro from the xbox guide.
Open the game.
Load the new Ranger Hardcore save slot
Once game loads, press X then quit to Main Menu
Load chapter, choose Finale, watch it and you'll get the Hardcore achievement.