- Actor Allusion: Billy Bob Thompson (the voice actor of Cross) has also voiced a Trainer who abandoned a Fire-type starter before.
- Celebrity Voice Actor:
- Edited for Syndication: Disney XD's showing of the movie entirely cuts any expository scenes that happen after the movie ends, replacing it all with a quick credits list.
- Milestone Celebration: The twentieth Pokémon movie, and one that hearkens back to the first episode as it's also celebrating the anime's 20th anniversary.
- Pop Culture Urban Legends: For a while, rumors floated around that the movie contained a stinger that featured Giovanni and Mewtwo, the latter clad in its armor suit from Pokémon: The First Movie. These rumors were later known to be false.
- Role Reprise:
- In the German dub, Pikachu is voiced by Sabine Bohlmann, who last voiced the character in the first season of the anime over 15 years prior.
- In the English dub, Michele Knotz reprises her role as Nurse Joy for the first time since the penultimate episode of the Diamond and Pearl series.
- The original Japanese version features Kyoko Hikami as Erika, reprising her role from almost 20 years earlier.
- Screwed by the Lawyers: While the English theatrical release of the movie includes a bonus music video celebrating most of the movies, Pokémon 4Ever, Pokémon Heroes, Pokémon: Jirachi: Wish Maker, and Pokémon: Destiny Deoxys are markedly absent, as the retrospective skips from the third movie to the eighth movie twice. This is likely due to remaining contracts with the original English distributor of those films, Miramax Films.
- What Could Have Been:
- The director of the movie had a few minor ideas for what this movie could have been, including a straightforward Sun and Moon-era movie and even an "All-Stars" movie, reuniting many of the past heroes and heroines with the current cast. Ultimately, they chose to go with the retelling due to the fact that, as a Long Runner, not many new fans knew how Ash and Pikachu first met.
- Veronica Taylor campaigned to reprise her role as Ash in the English dub of this film, but it was ultimately Sarah Natochenny who remained as Ash for this continuity.
- Word of God: It's been confirmed that Verity is not the daughter of Cynthia, the Sinnoh Champion, contrary to popular belief at the time.
- Word of Saint Paul: Director Kunihiko Yayuma revealed some behind-the-scenes information during an interview, including:
- This movie being a What If? scenario had Ash found the Rainbow Wing dropped by Ho-Oh.
- This version of Ash being more fashionable and his redesign being influenced by Ken Sugimori.
- The number of Spearow chasing Ash and Pikachu increased twentyfold, totaling 1,000!
- Shoko Nakagawa representing twenty years of the Pokémon franchise as she started from playing the original Red/Green versions, resulting in her being cast as Nurse Joy, an older sister figure.
- Ash being forever 10 years old, much like in the main continuity.
- The two Trainers in the opening are indeed Neesha and Corey from Pokémon: The First Movie.
- In contrast to the original Word of God on the subject, Verity isn't the daughter of Cynthia — her mother only resembles her and also happens to be a famous Trainer just like her.
Trivia / Pokémon: I Choose You!