Is there a specific number of humans that I can't kill so I don't get locked out of the good ending? In 2033 it didn't really matter how many humans you killed, just that you needed to show mercy when it counted and are open to peace. From what I heard, every human killed here counts as a negative, which is pretty damn annoying since there's no other way to knock people out than slowly going to them and doing it one by one.
Pretty sure you can't kill anyone other than the flamethrower guy at the end. You need to do other things as well though.I'm not sure if you need to do all these things, but this is what I'm going by. http://segmentnext.com/2013/05/17/metro-last-light-endings-guide-how-to-get-alternate-ending/