People will be talking about the inner working of Avengers: Endgame for a long time. One fan noticed a nod to Back to the Future: Part II over the course of the film. Now, the movie was bound to come up in the discussion of Endgame as time travel as a plot device is central to both stories. This is a bold homage to the earlier film infusing a scene that could have been considered a scary moment with some levity. Making things, even more, meta, the moment referenced in Back to the Future is itself a reference to Jaws. So, there are all kinds of cinematic intermingling going on in this moment. Rocket Raccoon is staring down the gullet of one of those giant flying creatures all over the last battle of Endgame. It looks like the Guardian of the Galaxy’s days are numbered until the beast disappears due to the snap from Tony Stark. The viewers basically see Rocket flinch for no reason. It’s a nifty little nod.
Endgame’s filmmakers invited all of that comparison to other movie depictions of time travel the second they chose to include that mechanic in their story. Even more interesting they didn’t shy away from mentioning the film by name in the movie as well. Endgame has a very peculiar relationship with time travel. Fans have been arguing about the final details of Captain America’s journey and the nature of the Marvel multiverse since opening weekend. Joe and Anthony Russo have both attempted to clarify the question of how time travel works for a while now.
Did anyone else catch this visual reference to Back to the Future: Part II in Avengers: Endgame? from r/marvelstudios
"That is a Back to the Future rule that is not applicable in our universe," Joe Russo directly answered the question earlier this year. "We're playing by a different set of rules."
Anthony Russo conceded that there were some very good reasons for why the future versions of the characters couldn’t mention their mission to people from the past. The Ancient One ended up being a big exception.
"You may be thinking about the fact that Doctor Strange doesn't want to tell Tony about what timeline they're in as they're going into the climactic fight with Thanos," Anthony began. "The difference between these two situations are when Smart Hulk is talking to the Ancient One, the Ancient One is no longer alive during the events that they're discussing whereas Tony is very much involved in the events he and Strange are talking about so there's a little bit of a distinction there."
"And that's just really talking to someone about this prior to their death," Joe added, expounding on that point. "You don't want to emotionally confuse them or create a situation where they no longer want to go through with what they are supposed to go through with."
"Especially when your chances are one in 14 million," Anthony said. "You have to be very, very careful about not messing it up."