Kingdom Hearts II Precursor

What if the secret movie is nothing but a prologue to the rest of the game?

After all, if the purpose of the movie is the same as deep dive, then maybe the events that occur in the movie won't occur withing the timeline of the actual game.

Just like in deep dive. After all, the fight between Roxas and Riku didn't even happen during the game. It happened beforehand, as evidenced by the cinematic scenes. What if the same is true with this movie?