A handful of actors did not reprise their roles from the first Kingdom Hearts: Billy Zane as Ansem, David Boreanaz as Leon, Mandy Moore as Aerith, Lance Bass as Sephiroth, Christy Carlson Romano as Yuffie, and Sean Astin as Hercules. Some fans highly disapproved of the use of such people playing the voices of the Final Fantasy characters, particularly Mandy Moore and Lance Bass. Interestingly, Sean Astin was replaced by the actor who originally voiced Hercules in the movie, Tate Donovan.
Besides typical English translation and localization, the English version of Kingdom Hearts II differs from the original Japanese version, in the content of game play and several scenes. The Hydra boss in Olympus Coliseum has its green blood from the Japanese version changed into black and purple smoke in the English version. An earlier cut scene retains the green blood. The World That Never Was boss Xigbar's telescopic sight view has been edited from the Japanese version to replace its cross-hair with three circles and remove the black shading around the sides that implied a telescopic sight. An attack animation was also altered; in the Japanese version, Xigbar combined his two hand-held guns to create a sniper rifle, which was used to snipe the player's party during the telescoping sight sequence. In the English version, Xigbar's animation does not combine his guns, instead twirling them around, and shooting at Sora with a single gun. Port Royal contains the most content edits. Cutscenes have been edited to remove some of the violence such as Barbossa's sword sticking out of Jack Sparrow's chest in one scene. Another edit has William Turner not aim his gun at his head as he threatens to commit suicide. Undead pirates, who act as enemies at certain times, do not catch fire when affected by Fire magic in the English version, unlike the Japanese version. Furthermore, the pirates' muskets have been slightly modified so to resemble crossbows, though they still fire with an audible shooting sound effect, and Sora's reaction command in response to this is still named "Return Fire". In the Japanese version, Barbossa talks of lust and women, of which translated into the English version is him just referring to "pleasurable company", however that change is to the line as it is said in the original film.
When "X" is removed from Xemnas and the letters are rearranged, you get the name "Ansem." Applying this to Roxas and Xehanort gives "Sora" and "no heart," respectively. This is applied to all members of Organization XIII, as their names are their real names rearranged and an X added, however only the original names of Ansem the Wise's 6 apprentices (Xemnas, Xigbar (Braig), Xaldin (Dilan), Vexen (Even), Lexaeus (Aeleus) and Zexion (Ienzo)) are given in the game.
Tetsuya Nomura included the worlds of The Lion King (1994) and TRON (1982) because there were his favorite Disney films. The Lion King (1994) World was originally going to appear in the first Kingdom Hearts (2002) game, but was removed due to the gaming engine for that game not being able to properly handle controlling a four legged character, which Sora would have to become when he went to the World. For this game, the gaming engine was completely redesigned, so Square was able to accommodate the necessity for the program required to make the playable four legged character. TRON (1982) was included because Nomura was inspired by and saw someone working on TRON 2.0 (2003), which was being worked on and released at the time of this game's development
Gaston's absence from the "Beauty and the Beast" world (Beast's Castle) makes him the only Disney villain so far not to appear in the Kingdom Hearts series with a world based on his movie featured as a playable level.
In the map know as Proof of Existence, 12 lighted tiles are on the floor representing the weapons of all the members of Organization XIII bar Xemnas, with blue denoting living, and red denoting deceased. Each member is represented by their weapon and their title, except for Ienzo (aka Zexion). His tile was deliberately put in as destroyed, so as to hide what his weapon really was (as his weapon was not revealed until the dual releases of Kingdom Hearts II: Final Mix+ (2007) and Kingdom Hearts Re: Chain of Memories (2007) in Japan).
Woody and Buzz Lightyear from Toy Story (1995) were originally planned to be new Summons in the Final Mix version of the game, but were taken out due to Disney/Pixar's relationship still being iffy despite the Final Mix version coming out about a year after Disney purchased Pixar. As well, Tetsuya Nomura did not want to include any majorly new Disney content that would ONLY be released for Japanese fans. Their models are still found in the Final Mix version's game code, albeit only as texture models
Allusions to deceased Organization members in Kingdom Hearts: Chain of Memories (2004), are made in this game. These members are No.4 Vexen, No.5 Lexeaus, No.6 Zexion, No.11 Marluxia and No.12 Larxene.
Disney Castle and Olympus Coliseum is the only worlds featured in this game, that exists exactly as it appeared in Kingdom Hearts (2002). Even though Disney Castle was not a playable world in the first game, the corridors and rooms look exactly the same. The Hades portion of Olympus Coliseum was not in the first game, but otherwise the Coliseum lobby, trophy room, and training grounds are exactly the same. The worlds of Agrabah, Halloween Town, Hollow Bastion, and Atlantica also appeared in both games, but their appearances from the first and second games are drastically different.
Each world has a unique symbol that appears on-screen during a scene transition when Sora moves from one area to the next. The symbols are the following: Twilight Town is a keyhole, Disney Castle is Mickey's head, Hollow Bastion/Radiant Garden is a crown, Land of Dragons is a Chinese emblem, Beast's Castle is a rose, Olympus Coliseum is a lightning bolt, Atlantica is a large musical note with 2 smaller ones, Port Royal is a skull & crossbones, Agrabah is a magic lamp, Halloween Town is a jack-o-lantern pumpkin, Pride Rock is Rafiki's wall painting of young Simba, 100-Acre Wood is a honey pot, Timeless River is a simple circle, Space Paranoids is Tron's disc, and finally, The World that Never Was is the Heartless symbol (heart with an X).
Axel is the only Organization XIII member you do not fight against with Sora, even though he teams up with him in Twilight Town. However, he can be fought as an optional boss in the Data Battles for Kingdom Hearts II: Final Mix+ (2007).
The costumes of the Final Fantasy VII characters of Cloud, Yuffie, and Aerith have changed from how they appeared in Kingdom Hearts (2002). In the first game, their costumes mirrored the ones they wore on FFVII, but in this game, their costumes mirror the ones they wore in the movie Fainaru fantajî sebun adobento chirudoren (2005).
Everytime the main 3 characters are called they are always referred to in the same order. Sora, Donald and Goofy. The only time they aren't referred to in that order is when you meet Belle in Beast's Castle she actually refers it as Donald, Sora, Goofy. Every other time it's "Sora, Donald, Goofy".
When Keiji Fujiwara was chosen for the role of Axel in the Japanese version, the makers of the English version wasted no time casting Quinton Flynn, as both voice actors played the role of Reno in Final Fantasy VII: Advent Children
All of the Final Fantasy VII character voices are the same actors from the Advent Children movie, with the exception of Yuffie, who was played by Christy Carlson Romano in the movie, but was played by Mae Whitman in the game. On a similar note, Yuna, Rikku, and Paine are voiced by the same actresses as their respective game(s).
The four Crystals from the Trophy in Twilight Town represent the four basic spells found in most RPG's: Blue = Blizzard, Red = Fire, Yellow = Thunder & Green = Cure. Interestingly, these also equate to the 4 main and Huge Materia from Final Fantasy VII (Support, Summon, Command and Magic respectively). Also, there is actually a whole level of magic that is not in Kingdom Hearts: Aja.
Eric kills Ursula by lancing her with Tritan's trident. This mirror's Ursula's intended demise in the original storyboards for The Little Mermaid (1989) (in the film, she was impaled by the bow of a shipwreck she hauled off the ocean floor).
Beast is the only Disney character besides Donald and Goofy that can help you in a fight against a member of organization XIII which is Xaldin. All the other boss fights against organization members you fight either alone or with Donald and Goofy (for the Absent Silhouette battles with the Organization XII members from Chain of Memories in Kingdom Hearts II: Final Mix+ (2007), the game only allows Sora to be aided by Donald and Goofy even though the symbols that led to each optional battle (excluding Lexaeus) took place in a world with a temporary party member which are forcibly swapped out) . The only other character besides them that helps you is Riku in the final fight against Xemnas. However, Riku isn't a Disney character.
The game's secret ending is meant as a tie in to the events of Kingdom Hearts: Birth by Sleep (2010). Additionally after the release of this games' Final Mix version, Kingdom Hearts II: Final Mix+ (2007), a new hidden boss known as Lingering Will, was also added as a tie-in (similar to how Unknown in Kingdom Hearts Final Mix was created as a tie-in to this game).
Xemna's line at the beginning of the game "I've been to see him, he is a lot like you" to Roxas is meant as a reference to the Final Mix version of Kingdom Hearts (2002), as Xemnas was secretly the hidden boss "Unknown" whom was exclusive to that version.