In a recent interview with Game Informer, Kingdom Hearts series director Tetsuya Nomura discussed more gameplay details for Kingdom Hearts III. While talking with Game Informer, Nomura discusses the new mechanic introduced in Kingdom Hearts III called Athletic Flow" (Japanese name), where it allows Sora to propel himself using the environment to reach new areas normally inaccessible. This mechanic also allows Sora to run up the cliff during the Rock Titan boss battle in past trailers. In English, this mechanic is known as "Flowchain".
You can check out the quote from Tetsuya Nomura below:
"It’s a new mechanic that we’re implementing in Kingdom Hearts III. The Japanese name is Athletic Flow. I don’t know what the English final name is just yet. It’s based on the Flow Motion mechanic, and it’s basically revamped and introduced as a new mechanic in Kingdom Hearts III. You’ll be utilizing the environment to propel yourself to an area that you’re not normally able to go to, or again, running up the cliff during battle. Those can be expected in each of the different worlds you’ll be traversing through."
Furthermore, Nomura also discussed summons and how it's more pretty compared to previous games, and how they're expressing summons in Kingdom Hearts III. You can check out the quote below.
"If I could provide a glimpse, I’ve made it more pretty. Not just the literal modeling, but it’s more about how we’re expressing it that has become more pretty."
Nomura also confirms that Keyblade transformations are based on what Keyblade you use, and there are 2 different forms that each one can take. However, Keyblade transformations are not finalized yet and they are subject to change.
You can check out the quote below:
"First and foremost, each keyblade will have its own form that it can transform into, and it’s different per keyblade. There are at least two different forms it can take. For example, in Toy Story, you saw the giant hammer and then the drill. Another one was at the beginning of the trailer where you saw Sora shoot arrows and it [then] turned into a bazooka, so there are two different forms. It also has multiple layers in terms of transforming; you start out with your first phase of transformation, and if you successfully connect your combos, the [next] transformation will happen. We’re still trying to finalize the specifications, but that being said, it is subject to change, so it might evolve into something even more impressive."