Trivia: Kingdom Hearts: Birth by Sleep

  • Acting for Two: Susanne Blakeslee voices Maleficent as usual, and also voices the Evil Queen and Lady Tremaine.
  • Executive Meddling:
    • There was no "Final Episode" originally, as its events were the end of Aqua's story mode. Also, the scene where Ven is absorbed into Sora's heart didn't originally have the framing scene with Sora and Riku on the beach. But the producers felt that it would be too depressing to end Aqua's story mode and the whole game itself on those notes, so Aqua's end got split into the Final Episode and the framing scene was added at the end of the game.
  • Fan Nickname:
    • Terranort and Venitas.
    • Before names were released, Master Xehanort was referred to as OBM (Old Bald Man; in the vein of BHK/Blond-Haired Kid for Roxas). When his name was released, we got affectionate nicknames such as Baldinort, Baldsem, Geezernort, Oldynort, and Grampinort.
    • There's the Captain Obvious-styled Evil!Sora for Vanitas. The epilogue also gave birth to (as seen below) KH!Jesus for Sora.
    • As well as Jesusora.
    • A less common one for Vanitas: Soranitas.
    • Red Eye for the unnamed Heartless that serves as the boss of the Secret Episode, later given the canon name Dark Hide.
  • Fan Translation: With the Final Mix version of this game. Like KHII FM, BBS FM was translated to English, this time thanks to Key To Truth. You must patch the game itself in order to play it in English, which you can do with either an ISO (for Emulation) or with an actual game cartridge.
  • Freeze-Frame Bonus: More of a blooper, though, but before fighting the Unversed alongside Mickey in Radiant Garden, if you look carefully behind Aqua, you can see a second Kairi right behind her.
  • Hey, It's That Voice!:
  • I Knew It:
    • Terra turns into Xehanort!
    • Ven becomes a part of Sora.
    • Sora's gonna save Terra, Aqua, and Ven from their fates.
    • On February 2009, a troper speculated the possible connection between the armor Xemnas wears in Kingdom Hearts II and the armor the protagonists wear. Two years later we got Birth by Sleep: Final Mix, aaaaand...
  • Playing Against Type: Leonard Nimoy, best known for playing a stoic, heroic character, plays a hammy villain here (although he still does keep many traits of The Spock).
  • Serendipity Writes the Plot: Final Mix+ showed the three protagonists of this game wearing armor with capes, the intention was to recreate that in-game. However, in the Mirage Arena the characters wear their armor, and giving them properly animated capes would have strained the PSP's CPU when going into multiplayer and several different players were running around. Thus, the capes had to go.
  • The Other Darrin:
    • Bret Iwan replacing the late Wayne Allwine as Mickey. Surprisingly averted by Chris Sanders, who still reprised his role as Stitch despite now working for DreamWorks Animation, Disney's primary rival in animated films, following behind-the-scenes conflicts on Bolt.
    • In the Japanese version, Captain Hook is voiced by Naoya Uchida instead of Chikao Otsuka, presumably because the latter voice actor was also voicing Master Xehanort.
  • Talking to Himself: Averted in the case of Captain Hook due to The Other Darrin (Naoya Uchida, who in fact is the usual Other Darrin for the Japanese Hook); in the rest of the series and in the Japanese dub of Peter Pan, Hook is voiced by Chikao Ohtsuka. Ohtsuka's in this game, but is playing Master Xehanort. And even if Ohtsuka did voice Hook here, the pirate and Master Xehanort do not cross paths anyways.
    • Played straight in the English dub by David Ogden Stiers, who plays two of the seven dwarfs (Doc and Happy); Russi Taylor, who plays Minnie, Huey, Dewie, and Louie, as well as the Fairy Godmother and Drizella (though the two don't have any scenes together); and Jim Cummings, who plays Pooh and Tigger. And that's just naming the characters who share worlds together! The actors mentioned (and a few not mentioned) play other characters as well, though those characters aren't even in the same world as each other.
  • Throw It In: According to Tetsuya Nomura, Miyu Irino had always wanted to play an evil character. So what does Nomura do? Make Vanitas into the polar opposite of Irino's other role in the KH series—Sora himself. Nomura jokingly states that he sort of got carried away with it.
  • What Could Have Been:
    • Nomura considered showing Leon and Cloud's past in the game, but decided against it because the Radiant Garden would have been overloaded with characters. And because, in his words, this game is complicated enough as it is.
    • Also, a Jungle Book world was going to be featured, but was pulled out. As one of the cut rooms was Louie's throne room, it may have been axed because of Disney's Louie embargo (see the Screwed by the Lawyers page's entry on TaleSpin).
    • Laguna from Final Fantasy VIII was also meant to appear as the head of the Mirage Arena, but was kept out due to his appearance in Dissidia 012.
    • Pleakley would've made an appearance in Deep Space.
    • The "Birth by Sleep: Volume Two" secret ending of Final Mix hints at a sequel for the PS Vita...that Nomura has now confirmed will not happen, as executive producers, for better or worse, thought there had been more than enough portable KH games, so the project was scrapped and focus was put solely on developing Dream Drop Distance and Kingdom Hearts III.