I only played the boss gameplay so I'll talk about that. There was another mode, the story one but I didn't play it because so many other people did. Sad thing is, not a lot of people were at the Atlus Japan booth this year. I can't blame though, as this year the booth was really, really small. No stage and everything(*cough*Where were you Kaneko?! Yamai?!*cough*) Seems everyone anticipated DDS2 more than this one last year. Heck, a lot of people were anxious to play DS PSP(which I got bored of due to I had no clue what to do) than DS:KR.^^;
Music? I could *hardly* hear any music from the demo. Why? Because that big flat screen TV hanging up on the ceiling was really loud and well, a lot of people were talking. But the music from the new/longer trailer was good.^^ It's the same music on the short trailer on the official site except you know, longer.
From what else I remember, there's no VAing in this game(*sad*) so anyone who liked Nocturne silent well, there you go. Moving mouths but no actual words coming out. I guess it fits the atmosphere more? I just wonder how they're going to do the FMVs dialog(probably dialog windows or something).
Boss gameplay gives you a fight right away. If I remember, the menu will pop out if you click R1 but I'm not sure. I didn't bother to try out the buttons "square" and "triangle". You can walk around freely on the battle screen(no wait) and attack anytime you want. I used Raidou's gun and sword most of the time(haha, just don't point the gun in the wrong direction like I kept doing. You get limited amount of bullets.) You can summon out one demon at a time and they mostly just healed me or attacked the boss. I didn't bother to look on how you or your demon can cast spells and other stuff though. Uh, the demons you call out in battles can also talk to you. =P But I think they just growl or say random things. Once you killed the boss the demo is over.
As for the other mode, it starts off with Narumi talking and then is shows frames of the scene where Kaya(rich school girl) gets kidnapped by those men in red. Anyway, the sun is shining and you're out in town now. Time to talk to that detective outside the office. Not sure I remember but he gives you hints/info(the hints/info are in yellow) about finding a young girl(or was it girls?). After, Raidou will call out a demon and I'm sure whatever demon you called out cast a fire spell(or maybe it could just be Jack O'Lantern though some did call out Mokoi when that happened) on the detective. This is the part where you're suppose to laugh? Raidou's the only one who can see demons so I guess while he was screaming, he was clueless as to why he was on fire?
So you wander around town and get random battles while you're looking for these two girls(which aren't far). Talk to them and one gets mad. I think this is the part where Gouto suggest to summon out another demon. I remember the old lady(yes, grandmas and grandpas can get their game on, too) called out Mokoi and he'll cast a spell on the girl. She'll then tell you infos and you have to find another girl named Rin(popular name in games these days?). After you talked to her, the demo ends and it'll show two screens featuring shots of the game. Pretty nice. (Yes, Mokoi was the most popular demon to summon out. He walked like he had to go to the bathroom or something.)
Demo was pretty short considering the other ones shown at the game show. More stuff on other TGS sighting I posted over
here.