I'm not really interested in giving away spoilers or details, but I will say, some of the things in this game are truly horrific, and the decline of the squad is imminent, yet very subtle. Uh... I haven't really played a game that made me feel the way I do playing this. It's not really enjoyable, but it is compelling and dark in a way that is... it feels very... real. The story feels like a mindfuck in the sense that it's so real, that it can't be real, if that makes sense.
I just... yeah.
EDIT: I will say though, the story is devious. It doesn't pose where, "the line," is and let you know when you're about to cross it. You've already crossed the line and you didn't even know it, and it... yeah.