When Famitsu talked to Tetsuya Nomura about Kingdom Hearts 3DS the magazine asked if players will see the same worlds. "No," Nomura replied, "except for original worlds and Traverse Town. We plan to make all new Disney worlds." The development team is currently in the processes of selecting worlds.
One thing for sure is Kingdom Hearts 3DS will have Sora and Riku as the main characters. Nomura is working on a way to differentiate the two keyblade users. An early screenshot released at E3 depicts both leads as children. When Famitsu asked why, Nomura answered "That’s still a secret." There is a reason for the change and Nomura explains having them as children is essential for the game’s story.
Kingdom Hearts 3DS will tie-in to Kingdom Hearts III’s story somehow. "Perhaps, the ending of Kingdom Hearts 3DS will continue in Kingdom Hearts III," Nomura teased.
Nomura closed the Kingdom Hearts 3D discussion by promising more information about Kingdom Hearts 3DS in the near future.