Just beat Metro Last Light on Ranger mode, and I got the good ending. So I was wrong, they did improve the karma system, basically make all good choices presented to you, and go through the game killing as few people as possible. I went through pacifist, basically.
And I'll have to download the demo for Gunslinger.
EDIT: Downloaded the demo for Gunslinger, aboot to try it. Also played some of the Artorias of the Abyss DLC for Dark Souls, it's good.
EDIT: Gunslinger is a lot of fun, neat comic book style, really kind of western movie feeling to it, with lots of the familiar bullet ricochet sound effects. One thing that's kinda bugging me is the portrayal of the guns, really nitpicky small detail stuff, but when you reload the single action revolvers, you don't eject the spent casings first with the ejection rod, you just slap a new bullet in, and then with the lever action guns, despite there being a loading gate present on the gun in the game, you load cartridges through the bottom, like a shotgun (which is strange because you load them through the side loading gate in Bound in Blood).