So I went through the demo real quick, and I had quite a bit of fun.
I never played the psp game so I have nothing to compare it with, but I personally love the change from the dark visuals to the more bright and... more accesable? looks. Well it makes sense for the 3DS platform so i'll leave the judging to those who played the original.
Gameplay wise I think not much may have changed, but being new to the game I am really loving the idea of this game. The demo has only a view levels and is rather short, but it allready sold me to buy this game eventually while before I had no idea what was so apealing about the game.
Even in the demo there are tons of unlockables you get from completing a stage. Goes from artworks to costumes. I always like some costumization features so this is a good reward system
SEGA has really made a good move in bringing out this demo among the very view demo's on the eshop. Crush was I think a very obsecure title so this may draw some more attention to it, especially since it's 1 of the 3 only demo's in the shop
Anyway, share your thoughtsK