It's OK IMO. What will probably keep me watching it the evil Sumire aspect.
Spoiler for Episode 1:
The look on her face as she stabbed into that monster was priceless. Seriously. However, I didn't like how she acted after she finished the monster and randomly turned on the eyepatch woman. A bit cheesy. Anyway, I'm off to rewatch that section.
Edit: And here's the exact face I reference:
Someone / some people mentioned it and yeah there's a sense of yuri. Sumire's school uniform there seems to resemble uniforms I see a lot in yuri anime from my perspective, too (I think).