Ok, I kinda guessed the tie in with the Mile High Club since the trailer featured an airport but where did the Brazil reference come from? Also, the 4 horsemen thing, that picture with Al-asad, Zakhaev, and Zakhaev's son with the red Xs on it and the 4th red X that we didn't recognise, I think we have "seen" the first horseman once. During the cutscene with the coup the driver of the car with Zakhaev's son was probally the first horseman. After all, the achievement for the first horseman is a man wearing a ski-mask and the driver of that car is wearing a ski-mask.