- Jossed: Following the original release of Kingdom Hearts: Birth by Sleep and the subsequent plot revelations that came with it, it was always thought that Xemnas sought out the Chamber of Waking in Castle Oblivion because the Terra side of Xemnas (which is more prominent in the Nobody component of Terra-Xehanort, being Terra's body and all) wanted to see his friend again. This game shows that, in fact, it was Xehanort all along who wanted to find Ven, because Ven is effectively an empty shell, which Xehanort needs for the real Organization XIII.
- The Other Darrin: Alyson Stoner once again replaces Hayden Panettiere as Kairi.
- Talking to Himself: Willa Holland gets in on this with Aqua and Phantom Aqua.
- Un-Canceled: 0.2 was originally revealed in Birth by Sleep's Secret Episode under the title Birth by Sleep Vol. 2, and was meant to be a new game in the series. However, it wound up getting the axe somewhere in the middle, but once the Compilation Rereleases started, it was revived and brought to its current form as a way to precede Kingdom Hearts III.
- What Could Have Been:
- Hidden in the files are unused assets, presumably for Kingdom Hearts III. These include first and second-tier versions of Fire, Blizzard, Thunder, and Cure; the Aero series (and, surprisingly, the Water series, albeit translated as "Aqua"); Glide and Superglide; Aerial Dodge; and Holy.
- As mentioned above, this game was originally intended to be a full on sequel to Birth By Sleep rather than just a prologue to Kingdom Hearts 3. Based on the teaser and what was salvaged for this game, it likely would have followed Aqua exploring the worlds from BBS and 1 that had fallen to darkness. Square Executives pushing Nomura to getting the production of 3 more underway led to the BBS sequel getting scrapped and retooled into this.
Trivia / Kingdom Hearts 0.2: Birth by Sleep - A Fragmentary Passage