No spoilers, as I am all of an hour into the game, so it's just mechanics and whatnot. The gameplay isn't turn-based like Nocturne - rather, it's real-time in a style very similar to the Secret of Mana/Seiken Densetsu games, although the battle screen is seperate from the field screen. I, personally, love it. I actually did enjoy the strategy Nocturne incorporated into the turn-based system, but real-time is where it's at for me. The two SNES Seiken Densetsu games are big favorites of mine (although I still need to finish them - stupid save files getting deleted).
The art-style is a little less stylistic than Nocturne, but more detailed in the environments - I think I'm going to enjoy the setting (1930's Tokyo), and they've done a good job fleshing it out with buildings and NPCs all over. It seems a little less overtly occult/religous in it's themes than Nocturne, and more historical, but I'm not quite far enough in to tell - I don't really mind either way.
And I gave the player character a non-lame name (is Raidou Kuzunoha a title? A name? An honorary name? I don't know), as opposed to my demi-fiend - Seichiro Makoto. Yami fans will get the first name, although I had to modify the spelling to fit the spaces, and the last name is the last name of the guitarist from a Japanese psychedelic band called Acid Mothers Temple that my brother likes.
Also, bitchy cat-demon FTW. Seriously, Gouto is like Mogget. I love him.