How to get the Kifflom achievement

Yes, you can get the achievement this way.

You can check your progress in the stats page from the main menu, although this will only show your progess in 10 wave chunks. For example, if you manage to complete wave 40, in the stats page you will see 'Wave 31 - 40' with a tick next to it. You can then complete wave 41 to 50 on another play through to get the achievement.

There is, however, a ribbon that you can get for completing wave 1 to 50 in one sitting (this is separate from the achievement, so you can view it as an additional challenge):

• Long Hauler – Completed all 50 waves in one session

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/