Graphics is good, L2D illust obviously, battle character is 3d looks like Overlord: Mass for the dead. Pretty nice to see.
Sound is good, the character has many lines. The music ...pretty good for my taste.
Gameplay turn-based, attacking animation really good not just simple movements but they go all out.
Storyline i recommend to watch the anime first since the story takes after... that... i don't want to spoiler just watch the anime first though if you want to read the story.
Value ...really good imo ofcourse the anime rated R+ but this game is global means all people can play so don't expect some [REDACTED] ,well... they still have *boing-boing* tho LMAO.
edit: ( ͡° ͜ʖ ͡°) version https://7sin-eng.userjoy.com/