31 things we learned about the making of 'Avengers: Infinity War' that answer pivotal questions about the movie

Joe Russo said Thanos was inside the Soul Stone briefly after he snaps his fingers.

"Thanos is transported through the power that was needed or required to wipe out half the life of the universe into this dream state inside the Soul Stone," he said.

So what's up with the version of Gamora he sees in this Stone World? Russo said that's the "spiritual representation" of Gamora.

Thanos "is allowed one last meeting with that which he gave up to get there," Markus said.

Anthony Russo summed it all up as "a fever dream" Thanos had.

"Thor could have a lot of guilt about his actions moving forward," Joe Russo said.

If Thor had only struck Thanos in the head, things might have been a lot different — but he had to get that quip in about revenge.

"He just went on the ultimate hero's journey, and it didn't work," Markus added.

"Tony starts the movie talking about the possibility of having a child and effectively loses one at the end," Markus said.

"This is a colossal loss for Tony," Joe Russo added. "As snarky as his relationship is with Peter Parker, he cares deeply about him. To have him die in his arms will change him forever."

Anthony Russo said one viewer had a funny name for the alien creatures seen during the Battle of Wakanda.

"Somebody was commenting on something that happened in this section of the film, and he said, 'You know those space dogs?'" Russo recalled.

He got such a kick out of it that they added it into the film as something Rocket says in the middle of the fight.

"Rocket refers to them as 'space dogs' when he's shooting at them," he said. "He's like, 'Come on, space dogs!'"

When Black Panther realizes that he, Captain America, Black Widow, and all of Wakanda are in dire straits from an impending alien attack, he makes a tough call for everyone to ride into battle head-on. He cries out the now famous phrase "Wakanda Forever" as they run off to what may be their death.

"We had no idea 'Wakanda Forever' was going to be amazing," McFeely said.

It was so amazing, in fact, that it became a meme, and the movie's release, Chadwick Boseman, the actor who plays Black Panther, later told Jimmy Kimmel that fans started asking him to do the salute all the time.

"We did not know — because we hadn't seen 'Black Panther,' because they were still making 'Black Panther' — about their war chants," Markus said. "And when the actors came from across Atlanta, from the set of 'Black Panther' over to ours to do this, they just started doing it. And it was impressive."

Joe Russo said that watching Winston Duke chant led to T'Challa crying out chants to the entire group of Wakandans.

Anthony Russo said he thought Duke, who plays M'Baku, was "just trying to heat all the actors up, and so the way they were doing that was with the war chant."

James Gunn was a producer on the film. McFeely said he was consulted.

Thanos tosses Gamora from a cliff in Vormir in order to retrieve the soul stone.

When Gamora and Thanos traveled to Vormir to obtain the soul stone, "Infinity War" offered an opportunity to insert the 2011 "Captain America: The First Avenger" villain back into the fold, and McFeely and Markus jumped at the chance.

The two have written the screenplays for all three "Captain America" movies, so they're very familiar with Red Skull and knew his story didn't technically end.

"Chronologically, he's the first guy ... well, and cinematically he's the first one ever to be obsessed with these Infinity Stones in the MCU," Markus said. "And he clearly did not die at the end of 'The First Avenger.' So the idea of where he might have gone was so tantalizing."

"When you get to Vormir and you get to the rules of Vormir, you're going to need an expert," McFeely said. "Whoever tells you what the rule of Vormir is, you don't want to doubt it. So that dovetailed nicely with a fetish Chris and I have of bringing Red Skull back into the universe."

Late in the movie, during the Battle of Wakanda, Cap jumps out to save Vision from a member of the Black Order.

"There was a point, there was a draft, where that tackle was Cap's first appearance in the movie," Markus said. "They called us insane. And we may well have been."

"After we read the draft, we did conclude that we were all insane," Joe Russo said.

Read more about the original decision to delay Captain America's entrance into "Infinity War" »

"I believe there is an existing myth of a gauntlet that could unify the stones. Hence the fake one in Odin's vault, and Thanos wearing this fashionable 'practice gauntlet,'" said Markus and McFeely. "When he needed a real one, he went to Eitri. Who also provided a handy carrying case."

According to McFeely, Strange would have worn an Iron Man suit in an alternate version of the rescue scene when Peter Parker and Tony Stark save Strange from Ebony Maw in space.

The scene would have also shown Iron Man wearing Doctor Strange's cape. Effectively, the two would have swapped outfits to save Strange.

It was one of a few alternate scenes that were "too awesome (and long)" to keep in the final film. Previously, concept art of Strange wearing the Iron Man suit was released, referred to as "Iron Strange" in "Avengers: Endgame: The Art of the Movie."

Joe Russo said there was a lot of discussion over how to get rid of Ebony Maw, but they realized there were so many more fight scenes to come that they didn't need another one that was drawn out.

"Eventually we decided that, you know, like [Indiana Jones] with the gun ... that something quick and efficient will be more surprising than something belabored, because there's an incredible amount of action in the movie," Joe Russo said. "It felt like we did not need another five-minute action sequence."

"We also just saw a fight between these exact characters in New York," Markus added.

Stark almost appeared in the scene when Steve Rogers, Wanda Maximoff, Vision, Black Widow, and Falcon meet up at the Avengers' home base. Joe Russo said it would have been a much different scene if Stark were there instead of James Rhodes to greet them.

"If Tony and Steve had to see each other for the first time, it would be much more complicated," Russo said.

"Which is why we didn't do it," McFeely added. "We tried in a few drafts, and it ground things to a halt."

The last time Stark and Rogers saw each other, Stark learned that Rogers' best friend, Bucky, killed his parents and that Rogers knew the entire time. They're not exactly on speaking terms.

The crew members pointed out that despite Rhodes' getting seriously injured by Vision and having every reason to not want to help them, his sense of responsibility to the world at large allowed him to put aside his personal feelings.

"Rhodey is once removed from that conflict," Russo said. "He's also an extremely heroic character, a military man, and understands that his sacrifice needs to be put aside for the greater good of the universe."

"This whole sequence once took place in Paris, where they were attacked by a swarm of Outriders. Things change," said Markus.

We never saw them fight the Outriders. They went up against two members of the Black Order.

"The Black Order, in particular, we worked hard to adjust them to the Marvel Cinematic Universe," Joe Russo said. "In the Hickman run, I thought the characters were too powerful. And nobody wants the sub-villain to outshine the villain. We adjusted their power sets so that they lined up in a way that was more interesting with our heroes."

For example, that's why Ebony Maw, who goes up against Doctor Strange, is a techno mage, someone who combines technology and magic.

"One is over her shoulder when [the Guardians] first arrive at the Ark and they see all the dead bodies floating in space. It's a very subtle shot of her twisting her head, knowing there's very few people in the universe who could enact that kind of destruction," Joe Russo said, adding that again on Knowhere, as she's landing, there's a realization "that they may be too late."

It looked as if the Hulk may have had some PTSD after fighting Thanos in space or being afraid of fighting him again, but that isn't the case.

"This was an interesting journey that we went on with Banner, trying to decide how to move him forward in the Marvel Universe," Joe Russo said. "What makes him unique is that there's a host body that is being fought over by two distinct personalities who hate each other, and both want control of the host body. We thought an interesting direction to take him in is: Well, what if Banner, who typically uses the Hulk to solve crisis situations — what if the Hulk were no longer interested in solving those problems for Banner? The relationship is becoming increasingly dysfunctional."

Russo added: "He's tired of playing hero to Bruce Banner."

When we first see Peter Parker (Tom Holland) in "Infinity War" he's on a school bus, and the hair on his arm raises up as we see his spidey sense go off. The Russos said there wasn't any computer-generated imagery involved.

"In our New York Times anatomy of this scene, we finally revealed," Anthony Russo said. "A lot of people think it's a CG shot, but it was actually achieved by a very gentle blowing on Tom's ear."

Imagine your job was to blow on Holland's ear for "Infinity War."

"We had a phrase in the room that we would call 'strange alchemy,' and that is not in reference to Doctor Strange, but in reference to the word 'strange,'" Joe Russo said. "So call it 'weird alchemy,' 'peculiar alchemy,' 'interesting alchemy' — we knew that this movie, in particular, being a crossover event that what would be some of the most entertaining stuff in the movie is how these characters who have never interacted before would interact."

They put together characters who could bring the most out in each other.

"A lot of the work that we would do, the four of us in the room together, we would be talking about what are the interesting combinations between characters?" Russo continued, adding an example: "Well, Tony Stark is a man of science and a narcissist. Doctor Strange is a man of magic and a narcissist. There seems to be a very compelling conflict of personalities there."

In case you were wondering, "Infinity War" transpires over a short period of time. Otherwise, the Avengers — and Thanos — would have needed to catch some sleep.

"It can't be more than maybe two days," Markus said.

Happy and codirector Joe Russo could have showed up during the park scene early on.

"This park scene was originally much longer, and included such notable actors as Jon Favreau and Joe Russo," said Markus.

Nova, a character who would have survived the massacre of Xandar, would have warned Earth about Thanos. Instead, we saw the Hulk crash down to Earth.

"It was an early idea, but we just reached a critical mass of new characters, and after we got rid of the Xandar sequence, it didn't make much sense," said Markus.

At the film's start, Thanos brutally kills Loki in front of Thor by choking him. Though fans wanted to believe he could still be alive, the filmmakers wanted to establish the tone of "Infinity War" early in the movie.

"Part of what we wanted to do out of the gate was to unsettle you as you're watching the film," Joe Russo said. "You're sitting in the theater thinking most characters in the Marvel Universe have been safe for a decade. And we wanted to knock you off-kilter and make the audience understand that the stakes were going to be significant and the cost was going to be very high in the movie."

The directors also said Loki's death was needed to set Thor off on his main mission to create a "Thanos-killing weapon" and come close to killing the Mad Titan.

"Aside from introducing Thanos as our lead and POV in the movie, this scene also very heavily kicks off Thor's arc in the film, who arguably may have the second-most-complete hero's journey in the movie," Anthony Russo said.

Read more on why you shouldn't have been surprised by Loki's death »

The first "Thor" movie introduces the Bifrost, a portal that allows people to travel throughout the nine realms. In the 2011 film, the portal is accessed via the Bifrost Bridge (aka the rainbow bridge) used by Asgardians like Thor and Loki. After it was destroyed, it looked as if anyone could just conjure up the Bifrost whenever they deemed it necessary.

Markus acknowledged in the commentary that it looked like "a bit of a paste job," but they made a simple fix for it in "Infinity War." In the movie's first few minutes, Heimdall shows he can channel the magical Bifrost portal by accessing dark magic.

"In 'Avengers One,' where Thor comes back saying that 'Odin used all his dark magic to get me home,' people said, 'Oh, that was just a cheat, because you broke the Bifrost' — and you just saw where the dark magic came from, straight out of Heimdall," Markus pointed out.

"This is to show that Thanos, the Genghis Khan of the universe, is unbeatable in one-on-one battle," Markus said. "He's conquered thousands of worlds. He's a much more polished fighter than the Hulk. And he dismantles the Hulk fairly quickly."

Again, because the Black Order's backstories aren't in the film, this isn't very clear. But there is one moment in the Edinburgh train station where the marriage gets a small nod — if you're paying attention or in the know about the comics.

"In the books, there's a backstory between Proxima and Corvius that they're married," Joe Russo said, adding that it's "only hinted at in the slightest way here by the fact that they're paired up to retrieve a stone and the way that she responds — the way that Proxima responds when Corvus gets stabbed by Natasha."

Kenneth Branagh, the director of "Thor," voices the distress call heard at the film's start. You may have missed a part of it upon a first viewing because it unexpectedly starts up as background noise in conjunction with the Marvel Studios' logo on the screen.

"This was an amazing surprise, by the way," Joe Russo said. "We had this idea very late in the editorial to ask the amazing Sir Kenneth Branagh to come in and do the opening distress call over the logo that carries us and sets the stage. It carries us into the scene with Thor and Thanos and Loki on the ark."

"There was a time this little Gamora intro started the script," said Markus.

The scene winds up much later in the film instead.

The team did consider including Xandar in "Infinity War" but decided the audience was smart enough to piece it all together.

"We wrote versions of Thanos attacking Xandar, and it had a similar purpose in the script to what Knowhere does now," McFeely said. "It was a place where Thanos and Gamora encountered each other.

"The fact of the matter is ... if Thanos went to Xandar to get that stone, you know what happened," McFeely added. "There was a big battle, and he got" the Power Stone.

We find out the planet of Xandar from "Guardians of the Galaxy" was destroyed by Thanos off-screen, but they did consider putting it on screen.

"An entire attack on the Nova Corps, but in the end, it was a beat you could fully understand without seeing it," said Markus during the two-year anniversary.

If you could have used some more info on the villains of "Infinity War," know that was originally part of the plan. But the Russos decided there were already way too many characters in this movie to juggle, and they wanted to keep the story as simple as possible.

Thanos needs to get the stones. Everyone is trying to prevent that from happening.

"Ultimately, the movie was getting too crowded, too hard to follow," Joe Russo said.