Well, it is from Gainax after all.
Sure thing! Does that all pertain to the ending or are there some general things too? If so ask away.
Some general observations regarding Miyu:
I really like the flute theme, and that she sometimes shows up playing the flute. Reminds me a bit of Robin Hood's leaf music. In the same vein, the understated fight scenes with Larva are pretty good too. The intro/opening credits are really great too.
The animation is okayish. It fits the show, but it's sometimes a little choppy and often makes use of stills. There are moments I find myself wishing that they'd spent less time on the backgrounds and more time animating these scenes too, but hey, there barely is any animated stock footage (reused backgrounds), so it evens out, kind of. Style is... a mixed bag, really. I like how Miyu looks, but Chisato sometimes looks like a bug-eyed alien thing.
Yukari looks like some character I know but don't know where from. That's such a bizarre feeling. It's more than her looks, the expressions, way of speaking, it screams familiarity at me, and I have no idea why.
The art and animation is best when it's trying to be moody and brooding, i.e. when (sucessfully) invoking a sense of dread and misfortune to come. The school scenes, not so much, not sure. You're right, the 80ies OVA looked much better overall. I still like it.
I see you've found a particularily lighthearted alternative to keep you occupied in between the heavy hitters.