The trailer starts off with Sora and Riku sitting out by the starfruit tree on Destiny Islands. Then Riku disappears in a swirling flash of light. Sora calls after him and runs around the island (the game switches to gameplay here).
Sora runs through the island a bit, showing off the locale. It looks exactly like it did in the PS2 game. The thing that makes me think it's not a port is that Sora already has the glide ability, which he uses to soar around the island a bit.
The game cuts again and shows Riku waking up Traverse Town (the main hub world of the PS2 game). He goes into a courtyard and is surrounded by a bunch of Heartless. Then he looks up and stuff gets crazy.
The sky starts raining Soras.
No seriously. A dozen unconscious Soras slowly float down from the sky like a cute boy meteor shower.
One of the Soras lands and busts out his Keyblade. The game switches back to gameplay mode here and shows Sora bashing the Heartless. After all the Heartless are defeated a huge soldier Heartless boss rises from the ground. Before Sora can battle him he snaps awake, back on Destiny Islands, sitting with Kairi by the starfruit tree. The camera pans up to the night sky and shows the title screen, Kingdom hearts DS.
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