Director Hideaki Anno told the actors to speak faster than usual so that they would resemble actual politicians and bureaucrats, citing Le réseau social (2010) as a reference and warning he would cut the take if they spoke too slowly.
According to sources close to the production, Godzilla's design in this film is mostly based on his design from the original film from 1954, and is intended to appear very frightening.
For Satomi Ishihara, who plays a Japanese-American diplomat, the hardest part of her performance was learning English. She found out she was playing an American after being cast, and was shocked by the amount of the English dialogue she had to speak when she read the script.
Producer Akihiro Yamauchi stated that the title "Shin Gojira" was chosen for the film due to the variety of meanings the syllable "shin" could convey, such as "new", "true", and "god". While Toho's official international English title was "Godzilla Resurgence", the movie was nonetheless released in the United States under its original Japanese title "Shin Godzilla" at Toho's request. A possible explanation for this is that they want to avoid confusion with the movie Independence Day: Résurgence (2016). "Godzilla Resurgence" is still kept as the title for general international promotion and in other countries, however some territories (for example Germany) also released the film under its original Japanese title.
At one point in the film, all the TVs in an electronics store are showing the live footage of Godzilla's destruction of Tokyo except one which is playing the anime "Ochibisan" created by Moyoco Anno, who is director Hideaki Anno's wife. This is also a reference to the fact that one of Tokyo's six broadcast TV stations is notoriously reluctant to air breaking news.
Kihachi Okamoto: The legendary director appears as a photo double for Goro Maki, a mysterious scientist that disappeared.
Hideaki Anno: [trains] Trains, tracks, and crossing bells are important motifs, just as they are in the Evangelion franchise.