I don't know if there both still in the store, but there were two different demos for the game. One was more story driven while the other was more about the battles. Personally, I think the battle system and dungeons are very solid. You do have to go through each of them twice with the two characters, but there's variation because there are different folks with different abilities depending on who you're playing as. What really convinced me to get the game, though, was the story. There's many different angles to the story and the whole time you're trying to put all the pieces together. The game's definitely not gonna impress you with flash. Instead it's much more subtle and atmospheric. I could definitely see why someone wouldn't like it because it is a bit unconventional. But I personally find it to be very good and totally worth the money.
My Top 5:
Shadow of the Colossus, Metal Gear Solid 3, Shenmue, Skies of Arcadia, Chrono Trigger
My 2 nex-gen systems: PS3 
and Wii 
Prediction Aug '08: We see the PSP2 released fall '09. Graphically, it's basically the same as the current system. UMD drive ditched and replaced by 4-8gb on board flash memory. Other upgrades: 2nd analog nub, touchscreen, blutooth, motion sensor. Design: Flip-style or slider. Size: Think Iphone. Cost: $199. Will be profitable on day 1.
