Just a word of warning, I did not get this achievement after doing the story on normal difficulty. I had to redo the storyline on epic to get this, and the achievement stealth popped. I would probably suggest abusing cloud saves in case it glitches on you too. Maybe you can pull the cloud save and keep beating Sutyr on normal until you get the achievement to save yourself a playthrough. Or maybe it only unlocks on epic. I have no clue. Game's pretty fucking buggy.