yeah, no. I have read multiple one shots, and mangas where they have the one shot as chaper 0, and while they don't have to be self conlcusive, at least it gives you a general idea of where the story wants to go. This one is way too vague for that, like I was hoping for her to say something like "I am here BECAUSE you killed him" it is still vague, but at least it confirms she has porpuse rather than just being there to take it.
I don't want to be mean, but if it realy was a try for a serialization, I can see why it wasn't picked up