I think the point here is that Miyu is a scared and withdrawn girl with strong defense mechanisms. She can't believe that Ao would like her, and she's afraid of being hurt, so she reacts defensively by impulse. The way she acts when confronted by the other girls really tells you everything you need to know about her. She's terrified but she also refuses to back down, and seems incapable of taking the easy way out.
That’s the real Megane touch right there—the shy, bookwormish glasses girl we’ve seen a million times (and almost always thought was completely adorable—but I digress), BUT this one is also surprisingly tough, BUT the toughness hurts rather than helps (or at least makes things more complicated).
So, complex characters, atmospheric visual style, and open-ended or ambiguous plots. Not always what I’m looking for, but a very specific and distinctive flavor.
(And not in this particular story, but, in keeping with the author’s name, the glasses girl who is also a seductive hottie.)