When it first came out on the Saturn in 1997, then received a PSX port in 1999, it never came to the US. As of 2013, that changed with this new 3DS version. While there's nothing to really compare it to in America, there are a few notable differences that are pretty obvious. One such different would be the addition of an alternate anime opening, another would be a streetpass based function where you grow a demon to gain access to more demons not available during encounters. It's one very good game though, very enjoyable, I highly recommend it.
It is my opinion that games like this are more movie/story than play. I watched/read this game for about 20 minutes, then got to fight for about 5 minutes. Then more watching/reading. If you have played "Catherine", the way the story is presented is pretty much the same. The fighting reminds me of old Street Fighter type games. There could be more to it, but that is as far as I got.