This is the first Pokemon movie where the Pokemon are given genders and referred as such by the characters.
Images of Mewtwo, Lugia, Entei, and Celebi are hidden in this movie, referencing Pokemon featured in the previous movies.
During the credits, Anne and Oakely are reading about the Collector (a.k.a. Lawrence III) and his flying fortress that appeared in Pokémon the Movie 2000 (1999).
This is the first movie in which Team Rocket has no contact with the main characters. It is also the first movie in which they are not the last characters to appear before the ending credits.
The dub makes Annie and Oakley members of Team Rocket, but in the original, the two are working independently and never mention a relationship with Team Rocket or Giovanni.