Story: 9
Overall, it was kind of interesting to see what would happen next. It had multiple depressing background stories to most of the characters, which really bummed me out watching, especially one scene that involves Nyu/Lucy's past. But despite those individual scenes, it got you wanting to know what happens next after each episode.
Art: 7
Gotta say, I liked the actual anime art, but the opening scene with the theme song and everything, wasn't amazingly fond of. The song kind of represented the show in a dark way, but the pictures were kind of "Ehh...".
Sound: 7
The sound effects were good, but some of the character's voices I couldn't stand. I think, overall, I liked maybe 3 of the main voice actors in the show, but only 3.
Character: 8
I liked their appearances and the way they acted. It could have been a little more original, I mean I think we've all seen the whole "Human with the weird ears/horns on their head" bit enough.
Enjoyment: 6
Wasn't one of my favorite series. I liked the action scenes, but most of the scenes just downed the entire mood when it came to telling stories about the character's pasts. It was depressing enough to watch most of the characters suffer, but the ending was just kind of weak.
Overall: 8
I wouldn't really watch the series over and over and over again, but it's worth watching at least once in your life.
