Millie Bobby Brown expresses this in an interview with Total Film Magazine, as she is honored her big screen debut is part of the Godzilla legacy.
O'Shea Jackson Jr. made it very clear that he is a huge Godzilla fan in every interview he has had for the film, even expressing that Gigan is his favorite villain. He felt extremely excited to join the project and even acknowledged the coincidence of his friends and Straight Outta Compton co-stars Corey Hawkins and Jason Mitchell having worked previously in Kong: Skull Island.
B-Team Sequel: Gareth Edwards was originally set to return to the director's chair after taking a break from blockbusters, but he decided to take on Rogue One in that time instead, meaning that his break was delayed to the point where it encompasses the time he could have directed this.
Colbert Bump: The trailer's usage of "Clair de Lune" astonishingly has fans looking up for the music. It wouldn't be inaccurate to say that no classical music fans actually minds this.
Cowboy BeBop at His Computer: Promotional plot summaries indicated the film was going to be about all the four main kaiju vying against each other for supremacy, rather than a two-way war for the fate of the planet. The promo materials made it sound like there'd be less plot in the film than there actually was.
Creator Backlash: Played down slightly, since Charles Dance didn't seem to hate the movie or regret working on it. However, he ultimately proved somewhat unenthusiastic about it, rather bluntly stating that he nearly fell asleep at the film's premiere. That being said, he brought the same level of dedication to the film as he does all his projects and has also stated he is open to reprising his role in the future.
A cut scene from the movie showed Admiral Stenz delivering an It Has Been an Honor speech to the Argo's crew before seemingly being killed when his ship is destroyed by Ghidorah's Gravity Beams.
A deleted end credits scene showed Drs. Ilene and Ling Chen travelling to the Temple of the Moth, where Ilene's twin daughters are singing to a Mothra egg.
Doing It for the Art: Michael Dougherty clearly created the film with this in mind. The Kaiju fights, cinematography and even the modernized Akira Ifukube soundtracks were clearly made for Godzilla fans as he himself is one of them.
Fan Nickname: King Ghidorah's ditzy left head is given the fittingly unfitting moniker of "Kevin". Another alternative is "Kevin Ghidorah".
Milestone Celebration: The film was released during the franchise's 65th anniversary. More specifically, it premiered on May 31, 2019 - the 115th Birthday of legendary Godzilla composer Akira Ifukube.
Missing Trailer Scene: The scene from the trailer where Madison tries to contact Monarch is absent from the movie. However, it's present in the novelization and occurs just before she steals the ORCA.
Posthumous Credit: Despite succumbing to a subarachnoid hemorrhage in May 2017, Yoshimitsu Banno is given an executive producer credit for this film.
Production Nickname: All three of King Ghidorah's heads had their own names by the production staff based on the first three numbers in Japanese: Ichi (middle head), Ni (right head), and San (left head). The left head however has the distinct honor for having another name, being "Kevin".
Promoted Fanboy: Mike Dougherty explains in Tokyo Comic Con that he's a huge Godzilla fan, and that directing this film is a dream come true. To the point that he mentioned photoshopping the original Godzilla (1954) spines onto the Legendary Godzilla's back.
Refitted for Sequel: According to Godzilla (2014) art book, The Art of Destruction, the Godzilla corpse found in the beginning of that movie would have been discovered frozen somewhere in Siberia instead of the Philippines. It was changed because Man of Steel, a film from the year prior, had a very similar scene of Clark finding the Kryptonian ship frozen in ice. This film appears to rework it, this time King Ghidorah is found frozen in Antarctica.
Release Date Change: The film's release date was initially sometime in June 2018, but was pushed back to March 22nd, 2019. It was subsequently pushed back again to May 30, 2019 to avoid competition with Disney's Captain Marvel.
The Jakks Pacific Ghidorah action figure quite noticeably has a detachable left head, with a joint located higher up on the neck than the middle or right heads. Predictably, Ghidorah ends up losing his left head in the battle against Godzilla in Mexico, though he later grows it back.
Take That!: After Emma's "Long live the king" line, it immediately cuts to Godzilla demolishing a building that has a large poster of a lion hanging on it. Guess which film WB's rival Disney was releasing the month after King of the Monsters came out?
Talking to Himself: While not quite 'talking,' Jason Liles does the motion capture for both Rodan and King Ghidorah's middle head.
In the novelization, the corpse of a reptilian mermaid-like kaiju called Margygr is in the Castle Bravo base alongside the corpses of both MUTOs, Jinshin-Mushi, and numerous other deceased Titans; while in the film only the Female MUTO's severed head is seen.
The Art Book for the movie shows concept art of Gigan, Anguirus, Baragon, a titan resembling Kumonga, and most noticeably, a turtle titan that bears a close resemblance to Gamera. None of them make any appearances in the movie. According to Dougherty, the production team considered adding other Toho monsters to the mix at some point, but, gven the fact that each Toho character has its own rights which must be paid, they ultimately decided to cook up some new creatures for the Monsterverse's menagerie. That being said, there are still lots of undiscovered Titans, and the team did manage to sneak the skeleton of a creature that may or may not be Anguirus just outside Godzilla's underwater lair.
The artbook also shows a picture of Godzilla, Mothra, and Rodan together in Boston suggesting originally it was meant to follow the original movie and have them triple team Ghidorah before it was changed to a tag team match.
Word of God: Michael Dougherty revealed in an interview that Dr. Ilene Chen and her twin sister Dr. Ling are very much the Shobijin. This would have been revealed in a credits scene that unfortunately didn't get made because they ran out of time, where the adult twins would enter an ancient temple where a new set of five-year-old twins would be singing to the new Mothra egg that was mentioned in the credits.
Michael Dougherty confirmed in a tweet that the spots on Mothra's wings are meant to look like Godzilla's eyes in order to highlight their symbiotic relationship by saying that Mothra is Godzilla's "flagbearer" as well as Queen.
In another tweet, Michael Dougherty explained why Ghidorah was frozen in ice: Godzilla and Ghidorah's last showdown in the past ended with Godzilla beating Ghidorah, leading to the three-headed dragon to be encased in a tomb of ice in the Antarctic.
Working Title: Unsurprisingly, Godzilla 2. During production, the film was also called Fathom.
The film, along with Pacific Rim: Uprising, was filmed at the Oriental Movie Metropolis facility in China, which is owned by Legendary Pictures' parent company Wanda Group.