This is an explanation of the basic gameplay elements of Kingdom Hearts 0.2: Birth by Sleep - A Fragmentary Passage, a game exclusive to Kingdom Hearts HD II.8 Final Chapter Prologue. For information on Kingdom Hearts HD Dream Drop Distance, see its individual guide.
Kingdom Hearts 0.2: Birth by Sleep - A Fragmentary Passage takes place directly after Kingdom Hearts: Birth by Sleep and before Kingdom Hearts III. As such, it melds the combat styles of the two games. Adopted from Birth by Sleep are the Spellweaver Command Style (now "Style Change") and the Prism Rain Shotlock, as well as some of Aqua's commands (such as Magic Pulse, which is now integrated as a finisher in her regular combos). Aqua also retains her Cartwheel (dodge), Barrier (block), Double Flight (double jump), and Air Slide (aerial dodge) abilities from Birth by Sleep. Lastly, the Keyblade that she wields is the Master's Defender (Master Keeper in the Japanese version), which she used in the Secret Episode of Birth by Sleep Final Mix.
The command menu, magic finishers (referred to here as Magic Situation Commands), and limited use of Flowmotion (in the form of the Rail Slide) would make appearances in Kingdom Hearts III. The options on the command menu are as follows:
- Attack: This is the default option, and allows Aqua to perform combos with her Keyblade. Repeated use of this option will trigger the Spellweaver Style Change. Repeated use of this option while Spellweaver is activated will allow Aqua to perform Spellweaver's unique Finish Command.
- Magic: Firaga, Blizzaga, Thundaga, and Curaga are listed under this option in the menu, though the usage of shortcuts is recommended to access these magic attacks. Repeated use of Firaga, Blizzaga, or Thundaga will trigger the powerful Firaja, Blizzaja, and Thundaja Situation Commands, respectively.
- Items: The restorative items that Aqua collects throughout the game are listed under this option. These can also be set to a shortcut.
The game begins with a tutorial in order to assist new players of the series in becoming adjusted to the gameplay mechanics, and includes explanations of abilities as they become available. Story explanations of previous games are also available in the menu, as well as Objectives, which take the place of the milestones usually listed in Jiminy's Journal. Take note that chests containing Zodiac Relics, required to access the game's secret boss rush, and Lingering Memories are available only on subsequent playthroughs saved over a completed game file.