Very well produced, but oddly written...
The animation's freaking amazing, no doubt about it. And surprisingly, the voice acting is, as it rarely is in even studio productions, really really good.
Aside from that, I wish the episode were a little bit more comprehensive. I mean, the only plot points displayed are the ones the viewer literally sees on his own - for a premiere episode, it's missing any character development, logical story hooks, establishment of even a little of what the hell is going on, etc. If this weren't so well produced, I'm sure not as many people would be excited about the next episode as there are now. Don't get me wrong, I'd love to see the next one too, but this felt more like a teaser than the first whole part of an epic.