MGS3 did that first.
Actually come to think of it, I think this scene does what Druckmann's trying to do only so much better. MGS3 keeps track of everyone you ever killed throughout the game, and the game remembers how you killed them. For example, if you blow someone up, they'll comment about their flesh burning. The fight with the Sorrow and its difficulty is entirely dependent on how many people you've killed so far. The game never makes you try to feel bad or get you to feel guilty, but seeing the number of people you've killed so far does provoke an emotional reaction, like holy shit I've killed a lot of people. It's actually a lot more natural because it's dependent on your choices, and the game's showing you how those choices ended other people's lives.