[keybored]

Slaying people is optional in MGS2 and higher, gameplay-wise. There’s not even a dilemma as long as you can handle hand-to-hand combat and a dart gun.

[pseudosavant]

I think that is one of the things I've always loved about the Metal Gear Solid games. Killing NPCs is something you can definitely decide to do, but there is almost always a consequence for it. The games' mechanics reward less violence. But is still a choice for the player to make on which path, and set of consequences, they want to have.