Question #1: Why can’t Iron Man & Co. wait for Captain Marvel’s return to pull off the Time Heist?

Seriously, why the rush? They’ve waited five years, what’s another few more days or months even? First, send out an SOS to Captain Marvel (Brie Larson) who’s busy saving other planets affected by Thanos’ killer snap. During the interim, they can refine the Time Heist — to steal the Infinity Stones in the past — and consider the ramifications of their timeline-messing actions. Strength in numbers, right? Better yet, travel back to 1995 and give Captain Marvel a heads up of the Thanos problem. And while they’re at that, why not also warn Nick Fury (Samuel L Jackson) not to get too friendly with Goose?  

Question #2:  Is Earth the only place with proprietary knowledge of the Quantum Realm?

Hate to be a party pooper but how is it that no one else in the vast, vast cosmos has thought about travelling back in time to undo the damage Thanos did? Look, we’re dealing with highly advanced alien civilisations, like the Kree and the Sovereign, that are capable of building interstellar prisons, warp-speed-ready vessels, and WMDs that can wipe out planets. Surely their brightest and smartest scientists — their Hank Pym (Michael Douglas) — have figured something about the miniaturisation and intricacies of the Quantum Realm and how to use them for time-travel, right? Just saying.

Question #3: Speaking of time-travel, how does it work in Avengers: Endgame? It doesn’t play by the rules of Back to the Future (change the past, change the future) and Legends of Tomorrow (you can’t return to a time and place where you changed the chronology once)?

According to Bruce Banner (Mark Ruffalo), history tampering doesn’t affect the events that have already happened in your timeline. So neither destroying the Infinity Stones in the past nor strangling baby Thanos will prevent half the universe’s population from being wiped out in Infinity War. The Ancient One (Tilda Swinton) later adds that removing the stones would create alternate futures. But Hulk assures her that the gems will be returned to where they’re taken from once the mission is over, thus preserving the existing timeline’s integrity. Does it really? Listen, time travel isn’t real, so writers are free to make this s*** up as they go along.

Question #4: Okay, I still don’t buy the bit where altering history doesn’t impact the future. Look what happens when the 2023 Avengers accidentally give 2012 Loki the Tesseract (aka the Space Stone) and allow him to escape. So Loki is alive…ish?

Actually, each time the 2023 Avengers revisit the past, they create an alternate universe but directors Anthony & Joe Russo didn’t dwell too much on the aftermath — because if they did, Endgame would’ve been three hours longer. So is there a scenario where Loki is raising hell on Earth with the Tesseract? It all depends on when Captain America returns the Tesseract to, 2012 or 1970. We’re never told. Either way, Loki’s whereabouts are unclear. The ambiguity is probably by design: to serve as an intro to his spin-off show that Marvel Studios is producing for the Disney+ streaming service. Devious. Like Loki.

Question #5: Which explains the ending where Captain America returns all the Infinity Stones back to their respective original timelines. Wait, it takes 10 people to recover the stones, but just one person to return them? Sure or not?

He’s Captain America. He’s a disciplined, focused multi-tasker. Then again, the movie never explains how he’s going to return the stones to their respective timelines. How is he going to liquidify the Reality Stone into aether and inject it back into Jane Foster? Or place the Mind Stone into the Loki’s scepter? Or (re)encase the Power Stone in the metallic orb? We think the writers came up with this problematic ending to mess with the audience’s minds. Well, they’ve succeeded.

Question #6: Does Captain America marrying his sweetheart Peggy Carter mean he’s no longer Captain America in the future?

After returning the Infinity Stones to their rightful places in history, Cap decides to take a detour and marries Peggy Carter (Hayley Atwell). The question is, by settling down and presumably hanging up his Captain America outfit, did Steve Rogers create a separate timeline where his alter-ego doesn’t exist? 

Or does he still get to be Cap but this time with Peggy by his side? Since he has that Quantum Realm GPS Tony invented, Steve can choose the timeline that best suits his lifestyle where he gets to be a crime-fighter and a family man. And when the time comes, old Steve zaps himself back to the 2023 timeline (he does have a time machine) where he was last seen with Bucky (Sebastian Stan) and the Falcon (Anthony Mackie). 

Another prevailing theory: Steve ventures to the same timeline shortly after the events of Captain America: The First Avenger, turns up at Peggy’s house, surprises her and marries her… secretly. They lead a secret life as the other events in the films — including Cap's own adventures — are unfolding. Many have speculated that Steve is the unnamed husband Peggy mentions in The Winter Soldier, who patiently waits for the right time to reveal himself to Bucky and The Falcon at the bench. (Cap did say in the Spider-Man: Homecoming post-credits scene that “patience is the key to victory”.) 

Both theories raise more questions. One, do we negate everything we know about Peggy on her TV show Agent Carter. And two, which period did Steve the shield he gave to The Falcon come from?

Question #7: Wait, if Captain America returns the Soul Stone to Red Skull at Vormir at the right time, does that mean he can bring Black Widow (Scarlett Johansson) back from the dead?

You wish. Red Skull did refer to the sacrifice made in exchange for the Soul Stone as “everlasting”. In other words, it’s a ‘no refund’ deal. In the comics, the Soul Stone houses a portal known as the Soul World where, as the name suggests, the souls of those sacrificed for the gem are imprisoned. Natasha and Gamora (Zoe Saldana) are probably comparing body scars and swapping boyfriend stories and as we speak. In theory, Black Widow isn’t dead-dead — just locked away. There’s a maxim among comics aficionados: no-one stays dead except Uncle Ben. Perhaps Scarlett Johansson’s agent can negotiate her ‘release’.

Question #8: How is it Captain America can wield Thor’s hammer, Mjolnir? Is Cap an Asgardian God as well?

“Whosoever holds this hammer, if he be worthy, shall possess the power of Thor!”, so says King Odin (Anthony Hopkins) in Thor's (Chris Hemsworth) first movie. And — guess what? — Steve Rogers is deemed worthy by Mjolnir. It’s that simple. In the comics, the Cap has held Thor’s hammer on a few occasions… er, that sounds weird. In the MCU, only a few have touched the Mjolnir. In Age of Ultron, the Cap tries unsuccessfully to lift it (at a party), but it’s Vision (Paul Bettany) who can effortlessly hoist it. In Thor: Ragnarok, Mjolnir gets destroyed by Thor’s black sheep sister Hela (Cate Blanchett).

Question #9: How come there’s no post-credits stinger in Endgame?

Really, that is your burning question? There’s a good reason for the omission: the ‘Infinity Saga’ — spanning 22 movies — is over! There’s nothing else to tease. What about Spider-Man: Far from Home? Well, they could have done that. But I think Marvel Studios prefers to start off with a clean slate with that one. (And the movie is already three hours, it doesn't need to be any longer.) 

In lieu of a bonus sequence, the directors have embedded an Easter egg at the tail end of the credits: the sound of hammer clanking on metal, which is lifted from the original Iron Man in the scene where Tony Stark is forging his armour suit.

Update: An earlier version of this story mistakenly identified Spider-Man: Far From Home as a Phase 4 movie. That is incorrect: Far From Home is a Phase 3 movie, the last one in fact.