I think stalker is not that hard, just need to understand accuracy and enemy flinching mechanics in the game. Isolating and then tapping away at enemy at center of the body to continuously stagger them is the safe way to avoid damage. And the further in game you go the better weapons you get, so eventually you can just consistently hit headshots. And avoid reloading save, do it all in one go. Because reloading saves triggers NPCs to start respawning to come into level from transition points. Aaand, need to beef up with bulletproofing(armor, artifacts) and avoid using soul/meat chunk/stone blood, because those makes you so much weaker to bullets it's not worth using them while in combat. I also thought stalker was so ridiculously hard because I kept dying from single bullet, because I was stacked with Soul artifacts.