For a spin-off manga based on a game that is the definition of spin-off, this has a really good story, by what some of you said there is a perceptible difference but i think the flow of the story, how the characters interact and act really engaging.
I having fun.
This manga serves as proof too that Ohmori Aoi-sensei really needs to find a writer to co-author his mangas, he has good art and style but he is really bad at planning a story even if has good conceptual sense, his other work always have a point where the storytelling gets... strange and the pace gets thrown off, which saddens me as i really like his style, hope this series opens new possibilities for his future.