Shaymin's voice is deeper when it is in Sky Forme than in Normal Forme. In the original Japanese, the accent was different instead.
Origin Forme Giratina and Sky Forme Shaymin debuted in this movie prior to their game debut in Pokémon Platinum.
The movie shows Eevee and the seven Eeveelutions at the time (Jolteon, Flareon, Vaporeon, Espeon, Umbreon, Glaceon, and Leafeon) during the opening sequence.
This is the first Pokémon movie to be a sequel of a previous movie. Although Pokémon: Mewtwo Returns (2000) is a sequel to Pokémon: The First Movie - Mewtwo Strikes Back (1998), it is an anime special rather than a Pokémon movie.
Lucas and Brendan make a cameo in the opening of the movie, battling with Magmortar and Rhyperior, respectively. This may reference the meeting of their female counterparts (May and Dawn), who battled in the finals of the Wallace Cup.