Kingdom Hearts HD 2.8 Final Chapter Prologue

Kingdom Hearts HD 2.8 Final Chapter Prologue, stylized as Kingdom Hearts HD II.8 Final Chapter Prologue, is a compilation of three  titles set as a follow-up to Kingdom Hearts HD 1.5 ReMIX and Kingdom Hearts HD 2.5 ReMIX. The titles feature HD graphics, and are composed of a remastered version of Kingdom Hearts 3D: Dream Drop Distance, an immediate sequel to Kingdom Hearts Birth by Sleep, and an animated side-story to Kingdom Hearts χ. The game was released in Japan on January 12, 2017, and was released worldwide on January 24, 2017 for the PlayStation 4, Febuary 18, 2020 for the Xbox One, March 30, 2021 on PC via the, and February 10, 2022 on Nintendo Switch as a Cloud version.

The collection was later re-released several times as part of combo packs, including Kingdom Hearts The Story So Far in 2017, Kingdom Hearts All-In-One Package in 2020, and Kingdom Hearts Integrum Masterpiece in 2022.

Development
The existence of Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage- was teased during "A Fragmentary Passage", the Secret Episode of Kingdom Hearts Birth By Sleep Final Mix that bridged the gap between Birth by Sleep and the original  and ended with the phrase "Birth by Sleep -Volume 2-". This drew speculation from fans that this ending hinted at a new game, especially when the game was localized outside of Japan in 2014 as part of Kingdom Hearts HD 2.5 ReMIX. In the October 2, 2014 issue of Weekly Famitsu, Tetsuya Nomura was interviewed and questioned about this new ending. He replied with “It shows the existence of Aqua’s story in the Realm of Darkness. It means that she didn’t just wander about in the Darkness for ten years, but that she passed through many experiences. However, it is a 'Fragmentary Passage,' as the name suggests – that story was severed and wasn’t told. I hope I can tell it when given the opportunity”.

In the credits for Kingdom Hearts HD 2.5 ReMIX, screenshots for Kingdom Hearts 3D: Dream Drop Distance are visible, similarly to how screenshots of Kingdom Hearts II, Kingdom Hearts Re:coded, and Kingdom Hearts Birth by Sleep were visible during the credits of Kingdom Hearts HD 1.5 ReMIX. Fans theorized this hinted at the game getting some kind of re-release. In September 2015, Square Enix announced that and HD remaster of Dream Drop Distance alongside a feature film adaptation of Kingdom Hearts χ, and an original entry titled Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage- would release as a collection titled Kingdom Hearts HD 2.8 Final Chapter Prologue in 2016 exclusively on PlayStation 4. On the topic of the name, Nomura would state that Kingdom Hearts: Dream Drop Distance is considered number 2.6 in the series since it follows the events in HD 2.5 ReMIX. The Kingdom Hearts χ games are considered 0 in Nomura's counting system because the series protagonist Sora does not appear. Birth by Sleep is 0.1, thus resulting in a 0.2 value for A Fragmentary Passage. When added together, the numbers total 2.8. .

Square Enix released a trailer for the game at Jump Festa 2015, where they revealed all entries in the collection are rendered in Unreal Engine 4, the same engine Kingdom Hearts III was being developed in at the time. Another trailer released at Tokyo Game Show 2016, featuring Simple And Clean -Ray Of Hope MIX-, a new remix of "Simple and Clean" made specifically for this collection. The game had an initial release date for December 2016, but was delayed and officially released in Japan on January 12, 2017 and internationally on January 24, 2017.

Kingdom Hearts Dream Drop Distance HD
Kingdom Hearts Dream Drop Distance HD is an upgraded version of Kingdom Hearts 3D: Dream Drop Distance that features an overhauled battle system and improved graphics. Reality Shift and Flick Rush are now able to be performed through the PlayStation 4 controller, and new Dream Eaters have been added, such as Catanuki.

Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-
Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage- tells the story of Aqua's journey in the Realm of Darkness leading into Kingdom Hearts III. Rendered entirely in and, it lasts as long as it takes to venture through a single world in a main-series game.

Kingdom Hearts χ Back Cover
Kingdom Hearts χ Back Cover is an 80-minute movie rendered entirely in Unreal Engine 4 and it utilizes the Kingdom Shader used in Kingdom Hearts III. It tells the story of Kingdom Hearts χ from the foretellers' perspective.

Xbox One release

 * User interface elements have been changed to fit the console.
 * The Disney Interactive Studios logo was replaced with the Disney logo.
 * The Unreal Engine 4 logo was replaced with the Unreal Engine logo.
 * There is an option to change profiles by pressing the X button in the game selection screen.
 * The Streaming Restrictions guideline is now called "Before You Stream...".
 * Extras is replaced with Screen Options which adjusts the screen.

PC release

 * User interface elements have been changed to fit the system.
 * The ESC key brings up a menu which contains options for Graphics, Framerate, "Before you Stream...", and to exit to Desktop.

Nintendo Switch release

 * The game is now streamed to the console through the cloud, using the technology provided by Ubitus.
 * All games can now seamlessly transition between docked mode and handheld mode.
 * User interface elements have been changed to fit the console.

Trivia

 * An insert for Kingdom Hearts 2.8 Final Chapter Prologue was included in releases of Final Fantasy XV. However, some of the inserts included the initial December 2016 release date that was delayed.