There’s an Easter Egg in Modern Warfare Remastered that allows you to pull a Flash and completely screw with the timeline, completely changing the events that would unfold in the sequels, Modern Warfare 2 and 3.
Eurogamer’s Ian Higton details in the video above just how to get this rare Easter Egg, complete with an ultra-rare trophy/achievement called, “Time Paradox.”
If you remember, in Modern Warfare 3, there’s a callback mission that sees your character in the car with the baddie Makarov. The reason it’s a callback is because in the first Modern Warfare, you play as the sniper that shoots Zakhaev. In Modern Warfare 3, Makarov drives away with you and Zakhaev, protecting him.
Well, in the first Modern Warfare, pre-remaster, Makarov doesn’t appear in the car. However, in the remaster, in order to truly join the games, they added him.
So, after killing Zakhaev, if you quickly bring your sights over to Makarov and kill him too, you completely change the timelines of the previous games.