Among the many highlights of the E3 trailer, we have Sora running up a vertical wall toward Lythos, the Rock Titan. When he reaches the top, we find that Lythos is much bigger than he's been in previous games, and Sora effortlessly takes several huge flying leaps up his body. Scaling a mountain and battling a Titan at the top? The whole thing has the air of a faster-paced Shadow of the Colossus or a less-bloody God of War. These kinds of maneuvers were semi-regular in previous games with the Reaction Commands of Kingdom Hearts II and the Flowmotion of Kingdom Hearts 3D: Dream Drop Distance, and the trailer seems to indicate that these two systems have been combined to give Kingdom Hearts III the wildest combat system we've seen yet.
Then you add in things like transforming keyblades (such as the BBS trio used), seeming special attacks based off rides (even against the aforementioned Rock Titan), even Shotlocks (as seen from the newest trailer), and well...
Another from the trailer, in the subtleties of the environment. Enemies burst out of a river and create splashes. Sora casts a wind spell, and the surrounding grass gets blown around. Anyone who knows how difficult that sort of thing is to render in CGI can surely appreciate it, and even though most video games have that much detail these days, it's an extremely satisfying art upgrade for the series. It's also a nice and sneaky way to reassure us that the game engine will be able to handle one of the most difficult pieces of CGI artistry in history: Rapunzel's hair.
This artwork of Sora flying on Baymax to fight a Heartless-possessed version of Baymax's original body.
The entire premise of the Big Hero 6 world - ever since Kingdom Hearts II, new worlds in the series have had a tendency of following their movie's plot exactly, making this brilliant original story a very pleasant surprise.
The Jump Fiesta 2015 Trailer. Nothing short of amazing in the gameplay department. As for 2.8, new story, and Riku, Kairi, and Mickey are rendered in the new style!