How to get Shadow Ranger achievement?

Question

I'm planning to run the game with Ranger Hardcore Mode, and wonder what I should (or should not) do to obtain the Shadow Ranger achievement?

In the description:

Complete the game without killing any Humans unless forced to.

But how can I tell when I am forced to kill? Maybe I could run to an open space, get agression and then kill all enemies?

---

I beat this game on Ranger Hardcore with bad ending (yeah, to get good one you need to explore every hole in this game and without killing somebody, mutant or human I think). And this you shouldn't do to get this achivement (plus only stealth walkthrough):

• You shouldn't hit NPC while they're on rails, on the level with Regina. Because I have one and could kill it with this train, if game doesn't count stuned enemies as object that you can't kill.

Next items is questionable, as said that there are no triggers for killing there.

• You should stun everyone at Red Square.
• You shouldn't shoot at level with Ganza train, while you going with Khan.
• You shouldn't kill anyone in the end.

I have done this things and don't get achievement. Also, you shouldn't kill anyone even if you're going to reload level.

Answer 1

You are only allowed to kill one human enemy in the entire game and that is the Flamethrower guy at the end of the game in D6, everyone else you have to either knock out or avoid. Be careful during the Contagion chapter as enemies have a habit of running into the fire and dying on their own, if this happens then be sure to restart the checkpoint. Always try to be stealthy, knock out the guards and going through Contagion quickly but carefully will help to ensure that you get this trophy. Be sure to check out the stealth videos for Separation, Facility and Revolution if you're having trouble making it through those levels.

• Chase: The beginning area can be somewhat annoying because crouching down will still allow you to take damage and the medkits don't seem to help much when you're being shot. I recommend having 4-5 medkits before starting Chase if possible, I also found that crouching and standing up every few seconds kept me from being shot as much then if I just crouched the whole time. Once on the train try to hide behind boxes as needed but know that they can shoot through most of them so try to keep moving, there are however some metal boxes you can hide behind that they can't shoot through once you get to the enclosed train car.

• Red Square: When you enter the square you will be surrounded by Reds on all sides of you. Your best bet is to hide behind the tall barriers until the guys start to walk up on you, disarm all of them and continue to hide until Pavel gets bored and opens the gate. As soon as he does run at the gate and disarm the guys. Note: You have to shoot at Pavel to continue the Chapter and make it up the stairs before you can decide his fate.

• D6: Stay crouched behind one of the small barriers and let the AI kill everything, there is a sniper on the wall to the left that you can use to shoot at the tank with. Note: There are ammo crates all around and there is a Minigun on the last platform that you can use to shoot the Flamethrower guy with.

I highly recommend following this link if you're having trouble: http://www.playstationworld.co/threads/3186-Metro-Last-Light-Shadow-Ranger-Guide

Note: You can kill Mutants just no humans so Spiderbugs, Demons and Watchmen are okay to kill. Also be aware that killing certain Mutants will affect the ending you receive.

Source: http://www.ps3trophies.org/game/metro-last-light/guide/