Originally, this was supposed to be Leonard Nimoy's final acting role before retiring. However, he liked playing Master Xehanort and being part of the series so much he wanted to continue voice acting, of which he does not consider "acting" or "work". Unfortunately, he only got to reprise his role once for Kingdom Hearts 3D: Dream Drop Distance (2012) before his death in 2015.
Here are all the Organization XIII members real names: Braig, Even, Ienzo, Lea, Isa, Dilan, Aeleus.
Aqua's design was changed due to censorship. Aqua's back was exposed so it had to be covered up. Aqua's hair & eyes were a dark shade of blue and it lack sheen.
A World based on The Jungle Book (1967), was to appear in this game, but was taken out for timing constraints and similarities to the jungle located in the Neverland (Peter Pan (1953)) World. The World was also supposed to appear in the original Kingdom Hearts (2002), but was taken out there due to similarities to the Deep Jungle (Tarzan (1999)) World. The World can still be accessed in this game's code (in the Japanese Version anyway), with areas such as King Louie's throne room, a mountainside on the way to the Man Village, and a river with giant lily flowers to cross to play in.
Zack is the only Final Fantasy character to appear in this game aside from the Moogles.