Actually, I think that in the entire movie, everything Roninspoon bemoans, was actually created this way intentionally, IMHO. We see a horror story, with vampires, heavy fighting and horrendous transmutations, with next to no character development, but visually compelling. This all just serves to underline the real horror, which Roninspoon's writeup omits, unveiled only in the last scene, when the credits start rolling, and that is the horror of war:
Let's look closer: We see an US B-52 bomber taking off of Yokota Air Force Base in Japan, it is the Halloween night of 1966. With these visuals, an anchorman is heard talking about an airstrike on Don Hoi in Vietnam in retaliation for an attack on a US base by the Liberation Front. These are the last lines spoken in the film. They can't be there just for fun, so there must be a meaning. What do they mean?
The National Liberation Army was the name the Viet Cong used for themselves. And the bombings described are the escalation point of the Vietnam war, even though Mamoru Oshii took a little liberty with the timing and the location from which these attacks were launched, probably for dramatic reasons. The beginning of the deployment of massive reinforcements and Operation Rolling Thunder. So Oshii suddenly puts the entire anime into a real-life context, a fight between ancient mystical enemies into perspective of one of the most horrible wars in recent history. We just saw slightly more than half an hour of blood and gore, and then, in one minute, memories or stories of the same suffering and pain increased thousandfold, perpetrated not by monsters or mythical creatures, but inflicted by humans upon themselves.
The effect in my eyes is creating a strong, visually compelling image, and then making it all seem irrelevant in the blink of an eye, by hinting at something much worse. Oshii is and always was a great storyteller, and this movie is once more a masterpiece, for he tells one story, compelling and horrifying, by telling another one. I think this is also why the movie is so short: Making it much longer would only pull the viewer further from accepting the fact that the first part is just make-believe. It does not matter whether she is a vampire herself. We do not need monsters, for we are them; The end was no end, it was a beginning...
And for those who still need a proper ending, disliking the choice of the director to put the message above the story, well, you can be happy, as the manga by Benkyo Tamaoki, soon to be published by Viz Comics will indeed continue the story and provide answers for the loose ends left at the end of the movie. Actually set decades after the anime, the ancient race of vampires has faded further into the shadows — while the normal world only seems to become more vicious and inhuman every year. Saya is once again sent out by the shady U.S. governmental organization to track down and eliminate Chiropterans stalking teenage prey. On the way, she will uncover the truth about herself, about the Chiropterans and humanity itself, while a new and horrible danger begins to manifest itself. Good stuff...