Despite both Sora and Riku being the two playable characters, Nomura emphasized that Rikus is the main focus of the game as it shows the character's growth across the series.
The Grid was originally intended to be playable only for Riku, while Sora would visit Space Paranoids. Nomura instead scrapped this idea and had both Sora and Riku visit The Grid.
Originally, elements based on Fantasia 2000 were to be included in Symphony of Sorcery, in which Riku would go to those parts, and Sora in the original Fantasia, however, Nomura found that they "had enough to work with" with the original Fantasia.
Celebrates the 10 Year anniversary of the Kingdom Hearts franchise. In addition references to all the previous main titles for the series are included in the game.
When Young Xehanort takes Sora through a simulation of Traverse Town, he references the town's role in the entire series and Sora's journey's throughout it. This consists of Sora's first journey (Kingdom Hearts (2002)), Sora's journey through his memories (Kingdom Hearts: Chain of Memories (2003)/Kingdom Hearts Re: Chain of Memories (2007)), Sora's journey through the datascape (Kingdom Hearts Re:coded (2010)) and Sora's journey through his dreams (Dream Drop Distance).