The PS4 versions of the classic Kingdom Hearts games have improved load times when compared to the previous PS3 versions. In addition the slow lag time of activating Drive Forms in Kingdom Hearts II Final Mix or D-Links in Kingdom Hearts: Birth by Sleep Final Mix (unless if the player paused the game for a few seconds) have been fixed which was one of the glitches that Kingdom Hearts HD 2.5 had.
As of June 12, 2017 two new DLC was added to the Playstation Store. While one of these is an extended cutscene for 358/2 Days, the other is a Theater Mode for Kingdom Hearts Final Mix. Notably this version, along it's original version and the original version of Kingdom Hearts II did not have a Theater Mode to replay any voiced cutscenes that were throughout the game from the main menu.
Originally this title was used by Square Enix as the name of a two disc collectors special on the PS3 that was only sold on their official Kingdom Hearts website. However this 2017 release for the Playstation 4 is completely unrelated to the collector's set and is instead released on a single disc.
Much like with Kingdom Hearts HD 2.8 Final Chapter Prologue (2017), this title was released on the franchise's 15th Anniversary. However only this game is being advertised as the 15th Anniversary release, especially since 2.8 was originally intended as a 2016 release. Additionally this games' release in Japan is nearly two months after 2.8's release.
Much like with Kingdom Hearts HD. 2.8 Final Chapter Prologue, the Playstation 4 releases of Kingdom Hearts HD 1.5 Remix (2013) and Kingdom Hearts HD 2.5 Remix (2014) will also run at 60fps (frames per second). This is the only main change to these games compared to the original PS3 releases.
This is only other Kingdom Hearts game released not to feature any new footage aside from KH Final Mix for either the Japanese or English versions. All of the voice actors roles are archived from their respective original games' release or were originally released in both of the HD Collections' original PS3 release (namely the new cutscenes for the cinematic re-release of 358/2 Days and Re:Coded that were not part of the original Nintendo DS release, as well as the English version of the Final Mix-exclusive cutscenes from Kingdom Hearts II Final Mix excluding the scenes that were previously adapted for 358/2 Days, and the scenes from the Secret Episode for Birth by Sleep Final Mix).
This game consists of the largest collected edition for the Kingdom Hearts franchise and also contains six of the seven main titles. The only exception is Kingdom Hearts 3D: Dream Drop Distance (2012) as it is part of the third HD collection set, Kingdom Hearts HD 2.8 Final Chapter Prologue.
As a result of merging the two PS3 HD games into one for the PS4 release a new main menu for the game was designed to do so. Since unlike the original 1.5 and 2.5 releases as well as it's fellow PS4 release 2.8, as six games are involved in this set instead of three, they are lined up on the left hand side of the screen instead of spread across the screen like the previous releases. As a result a full-sized shot of the game covers when each game is selected is shown instead of it being partial (even though like in 1.5 and 2.5 Re:Chain of Memories' game cover is based off the one from Kingdom Hearts: Chain of Memories (2004) and Birth by Sleep Final Mix's cover is based off that version instead of the original game like the other Final Mix versions). However the credits from both PS3 versions are still kept as separate menu selections.
As the PSN Trophy List presents the PS4 versions separately, none of the trophies earned in the Playstation 3 version are compatible and therefore have to be collected separately. However the trophies for the two HD cinematic movies of Kingdom Hearts 358/2 Days and Kingdom Hearts Re:Coded are the only trophies to have been removed entirely from the Playstation 4 version.
A few minor improvements were made in earning a few trophies to make them less time consuming to acquire. The difficultly trophies from Kingdom Hearts Final Mix, Re:Chain of Memories, and Kingdom Hearts II Final Mix can now be stacked if that respective game were completed on a higher difficultly level. Additionally requirements for the Gummi Ship Collector trophy on KHFM has been lessened down to collecting 30 blueprints instead of all 48 blueprints.