Random Trivia For This Title:
- Before the film was released, there was much fan speculation that either Tony Stark/Iron Man (Robert Downey, Jr.) or Steve Rogers/Captain America (Chris Evans) would die in this movie since it was known their contracts were not extended past the end of the Avengers series. Ironically, they are two of the very few characters who are not killed. In fact, with the exception of the off-screen Clint Barton/Hawkeye's status unknown, all of the original Avengers featured in The Avengers are shown having survived at the end of this film.
- The reason Peter Parker/Spider-Man's death took so long was because his spidey senses made him realize earlier and his accelerated healing slowed it down.
- Zoe Saldana is reunited with [Star Trek] villains Benedict Cumberbatch and Idris Elba in this film, though she shares scenes with neither of them this time. She also shares scenes with Chris Hemsworth, with whom she never shared a scene in 2009's Star Trek. The role of Bruce Banner/Hulk, in the unrelated Hulk film, was previously played by [Star Trek] villain Eric Bana.
- Thanos fulfills the promises he makes. *He spares Thor in exchange for Loki giving up the Space Stone. *He spares Nebula in exchange for Gamora revealing the location of the Soul Stone. *He spares Stark in exchange for Doctor Strange giving him the Time Stone. All three promised lives survive "The Snap."
- The name Thanos is a short form of the Greek name Thanatos, which means 'death' in Greek.
- Josh Brolin based his characterization on Marlon Brando's role as Colonel Walter Kurtz in Apocalypse Now.
- Josh Brolin acted this scene with a foam headpiece that was the size of Thanos' head, with a camera on his face for VFX. He also had to wear various foam parts depending on what the scene called for so the other actors didn't get too close to his real body, and so Thanos' scale was retained.
- The filmmakers did not know about the war chants the actors from Black Panther created, as that film was not nearly finished at the time of shooting. Winston Duke had started the chant, which led to the responding war cry that Chadwick Boseman leads.
- According to Chadwick Boseman, production on Infinity War began just two weeks after production on Black Panther ended. This meant that all the actors and even the extras from that appeared in both films had no problem retaining their cadences.
- The filmmakers thought of the film as Thanos' hero's journey. That's the way they could figure out how to put everybody in the film.
- The filmmakers had a phrase to describe characters meeting and interacting for the first time that they called "strange alchemy." The conflict of personalities between Tony Stark and Doctor Strange is a perfect example of this.
- Just as they paid homage to their television show [Community] in the second and third "Captain America" films, the Russo brothers also included another easter egg from their other well-known show, [Arrested Development], in this movie. In Captain America: Civil War, the stair car from [Arrested Development] appears in the Berlin airport. In this film, blue Tobias Fünke from that same show appears in one of the Collector's display cases - he can be seen behind and to the left of Gamora in one shot.
- Josh Brolin claimed that he did not see Black Panther until a week before this film opened due to it being constantly sold out in L.A. Brolin added that stars of the Marvel Cinematic Universe don't receive any special privileges of screening passes to the franchise.
- The filmmakers wanted to create small physical rules that would allow characters to stay in the fight with Thanos. The idea of Thanos having to close his fist to use a stone was the bare minimum that allowed for a fight to be put up.
- Tom Holland said that although he is a big fan of Chris Pratt and loved working with him, their scenes together were often challenging. Pratt's tendency to joke in and out of character made it hard for Holland to keep a straight face at times.
- Kenneth Branagh (who directed Thor seven years earlier) can be heard at the very beginning of the film issuing the distress transmission that the Asgardian ship was being attacked.
- Doctor Strange has been studying for a few years since his solo film and is now considered one of the more powerful characters in the MCU. The writers also wanted to have him come off as sort of "the adult in the room" throughout the film.
- Hugh Jackman expressed interest to appear in an Avengers film, but he said he would only reprise his character, Wolverine, if he appeared in the Marvel Cinematic Universe. In December 2017, however, Jackman officially stated he would not be reprising the role and he would love to see someone else play the character, naming actor Tom Hardy as his personal choice. Logan was Jackman's last film as Wolverine.
- Drax's line "I'll do you one better: Why is Gamora?" was ad libbed by Dave Bautista. - In an interview Dave says that Chris Pratt actually gave him the idea for the line.
- The Russo brothers originally confirmed that Captain Marvel would be in this movie. However, Joe Russo later declared that the character would not, and she would instead make her debut in her own movie. The character will have a major role in Avengers 4.
- Chris Evans and Chris Hemsworth ad-libbed the dialogue between Captain America and Thor in which they compared their facial hair, reasoning that they have known each other long enough to have that kind of friendly banter.
- According to the Russo Brothers, Peter Parker's lines at the end of the film, where he says, "Mr. Stark, I don't feel so good" and "I don't wanna go" before he disintegrates, was improvised on the spot by Tom Holland.
- James Gunn made one change to the original script: originally, Peter was not able to bring himself to fulfill his promise to kill Gamora if Thanos captured her. In the final film, Peter does try to kill her, but is prevented from doing so by Thanos.
- Tom Holland was not allowed to read the script for this film, since he revealed too many secrets for Spider-Man: Homecoming. In one of the promotional videos for the movie, several of its cast members are in an interrogation room refusing to reveal any spoilers, and Holland's mouth is conspicuously taped shut.
- Mark Ruffalo revealed that he was given a fake script due to his habit of accidentally spoiling past Marvel movies. He jokingly claimed in an interview that the fake script was better than the real one.