And man, it looks awesome...
The battle against Darkside seemed much more fluid, and it looked like Sora was pretty pissed at Riku, which would have killed all the fangirls' hopes of SoRiku.
And the trailer for KHII looks better than the actual game too.
The beta of both games always seemed to be way better in my opinion (except the battle system...though Darkside looks like a better fight). I liked the end quotes. They were really emotional to me. And if Riku had said that first ending quote to Sora, he would have been even more kickass than he is now. And it seems to set up a better rivalry between the two. Because it shows that Riku was Sora's enemy from the beginning rather than secretly being controlled until Sora finds out that Riku has been taken over by SoD.
KH2 beta also showed the old castle which I missed in the final version KH2. They even made the CGI official art with them at the old castle and the Rising Falls.