The game fucks with you. You start thinking you being the hero in the story. But you keep doing more and more fucked up shit, justifying it all because the main character is blended by his sense of justice…aaaaaand a pretty heavy psychosis.
One of the most well known parts for example: You know these cool levels in CoD, when you see the battlefield from above with an infrared camera and shoot at targets on the ground? You do something similar here too. Just to see later that you just burned a refugee camp to the ground with phosphorus bombs. You get to see the whole horrific mess you just orchestrated.
Your teammates also make a lot of comments that only make sense later, when you figure out that you have lost your mind and talked to people who aren’t there, etc. probably to cope with the shit you are doing.