Development
Kazuaki Imai, who directed the previous Doraemon feature film Nobita's New Dinosaur, was replaced by Susumu Yamaguchi. Yamaguchi stated, 'I used to participate only in drawing, but it was over. However, I thought, I want to make a Doraemon film before I die. So I took the initiative and acted under the name of the 'five-year plan.'" He had previously worked on the production of TV specials and movies and appealed to the production team to direct this film. As a result, he was eventually chosen. However, because the production of an original film was difficult due to the schedules, Yamaguchi decided to remake Nobita's Little Star Wars. According to Yamaguchi, Nobita and the Castle of the Undersea Devil was also recommended, was not finalized because of the difficulty to animate scenes in underwater.[9]
Dai Satō wrote the screenplay of the film, who has worked on many works including the Science fiction anime series Cowboy Bebop. Yamaguchi said that he was glad with his screenplay.[9]
Koichi Maruyama was selected from the TV series for character design,[10] and Junya Ishigaki was in charge of mechanical design.[8]
Screenwriting
Sato had written his own plot to make the remake compatible to the 2020s age. After that, it had turned out that director Susumu Yamaguchi had also written a plot based on similar changes. Therefore, the two decided to pursue the character of Papi, the guest character of this work. In the original story, Papi was separated from Nobita and others by PCIA in the first half of the story, but since it was not possible to show the interaction between Papi and Nobita and Papi's feeling about it, Sato had consulted with Yamaguchi and had decided to write the first half of the original shorter. For the same reason, Papi's older sister Piina had been introduced as a new character.[11] In addition, the original Papi was depicted as "an intelligent life form far superior to earthlings," which was slightly changed in the remake to make it compatible to the modern times. For this reason, a scene in which Papi becomes emotionally angry was included.[11]
For characters other than Papi, a deep digging of the character was done. For example, in the case of Suneo, he was portrayed as a representative of the majority of people who want to be brave enough to do heroic things, but they only keep things to themselves.[12] Also, in the original work, Suneo showed a war-weary attitude which remained in the remake, but scenes were increased where Suneo was reluctant to fight.[11]
Casting
Among the guest voice actors, Mayu Matsuoka was selected as Papi's older sister, Piina. In an interview with Animate Times, Yamaguchi revealed that when he heard Matsuoka's first line, 'Doracoluru', he felt that Matsuoka was a good choice. In addition, the leader of the underground organization and the pilot of the Free Alliance, who were collaborators of Doraemon and others, were played by the comedy duo Milk Boy, Takashi Utsumi and Takashi Komaba respectively. In an interview with the Animate Times, Yamaguchi said that the two characters in the play are not comedy relief, but rather young people who are desperate to save their nation. Teruyuki Kagawa was appointed as Gilmore, the dictator of the planet Pirika. Yamaguchi revealed in an interview with Animate Times that he had asked Kagawa to play 'the most hated person' in a letter. He also said that Kagawa was acting with his body and gestures. Romi Park, Yuki Kaji and Junichi Suwabe were selected as Papi, Rokoroko and Dorakoruru respectively.[12]
Visual effects
Care was taken to keep the character designs close to the original, but not too old-fashioned.[10] Also, in the remake, as a respect for special effects films of the 20th century, real miniatures are used as part of the background in some scenes, which is the first time in the Doraemon film series.[12]
