I actually really like how it gave you a rough idea what the actual story is about. It unfortunate it isn't longer, I would have watched it. I think the fighting is nicely drawn. It is really hard to tell what type of story something will be about in such a short amount of time but I think the handled it very well.
I would really give this an 8.5 if I could because I do wish they would have made it flow a bit better. All in all a good 11 minute OVA.