Well this sure is a nice surprise. I don't think anyone was expecting to see actual gameplay from Kingdom Hearts 3, aside from the very short tease we got at E3, any time soon. And low and behold, we get almost a minute and a half of some sweet combat and summoning action.
The first part shows Sora, Donald and Goofy in typical Kingdom Hearts combat against the Heartless. In the very end of that portion we do get a very brief glimpse of Sora turning his Keyblade into two guns that he fires at the enemy.
After that, Sora is shown riding a Pirate Ship ride, adorned in parade lights, in what looks to be a Summon sequence, as it damages enemies surrounding him.
The very last part shows Sora and the gang riding what I presume is the Big Thunder Mountain ride as he's fighting the Rock Titan from Hercules.
While many are complaining that the visuals don't match those shown in the E3 trailer, keep in mind that this is still a very early build, not to mention. Sora is still wearing his Kingdom Hearts 2 clothes as well, which I'm fairly certain will be updated for the sequel.