It seems that some old demons from previous devil summoner games will be ported in 3D for this game, it's cool.
Also, i wonder if they will conserve the Loyalty System from Devil Summoner 1, which consists of a degree of loyalty from your nakamas/minions. If they have 0/10 they don't listen to your orders and boycot you, it was pretty fun (but hard, because we have a lot of demons who need to up their loyalty but not enough items to did it).
Also, Akineko, a "famous" japanese doujin band just made a new remix, and it's the boss battle theme from devil summoner. Enjoy, I always loved Akineko's music :
http://akihito.milkcafe.to/(direct link :
http://www.ismusic.ne.jp/akihito/sound/ds_boss.mp3)