the story : explains a bit about character mainly the 9th minene and a few other characters like how they first met ,etc its good for a bit of change as it is not as dark and in some part can be quite comical ^^
art : well like main story except not as dark / gruesome
character: see more character personalities developing in each chapters
enjoyment: if you love minene and nishijima like me lol or wanted to know a bit more about other characters that get eliminated early in the main story( and dont get to know them that well) then youll love this manga . full stop
lol i try not to spoil so yea ~
thats all
