I think compared to DeSu1's story, it's not that impactful but I still liked it regardless so it's a mixed bag for me. I loved and hated some of the characters, but generally I think character writing is ok.

Gameplay wise this sequel is a massive improvement with the race ability upgrades and some boss balancing that made it much better. DeSu 1 had infamous, massive difficulty spikes and the bosses will destroy you if you don't have specific demon team combos such as flight or phantasm with how huge boss ranges can be. I still dont like how mana is a precious resource, but it didn't become a huge problem in the end so it's alright for the challenge. I still love demon fusion with this game because you can create the most op and broken demons possible such as an all reflect demon I had that could only be damaged by almighty and wind skills.

Great sequel. Not perfect, but is a massive improvement gameplay-wise compared to the first DeSu.