"For the most part, we've established the foundation - the basic system and mechanics of what's going to go into the game," Nomura explained. "The development of that is close to complete."
Nomura's team is now working on executing this vision, which involves building in-game areas and fleshing out minor elements at the current stage of development.
"Since this title is in HD," Nomura said, "building resources and the mass-production of areas and other elements, including mini-games and other various smaller items, [takes time]. Some of them are polished to a close-to-final state. At the same time, some elements are still in the planning phases and we haven't laid out the groundwork yet."
"But the basic structure of what's going to go into the game is set," Nomura assures. "It's now a matter of mass-production of the different elements [within the game]."
Square Enix has made little mention of Kingdom Hearts 3 since it was announced at E3 2013, opening up fan speculation regarding its development status. A trailer released later that year showcased combat in an early state, and offered no hints at the possible directions the series' famously convoluted storyline would take.
For more details on Square Enix's upcoming releases, head on over to our E3 2015 hub.