Well, I just finished watching this anime at the suggestion of a friend.
First off, pretty decent anime, good and interesting storyline. The only problem I had was that the story seemed to jump around a lot or there were gaps in the plot(s) or story itself. (More on this later.) It felt like watching that good old-school RPG from the 16-bit days turned into an anime.
Animation was decent but it looked like it dropped in quality a bit towards the last few episodes.
I really hope there is a second season that does fix on the aforementioned problems. For example, keep the plot and story consistent.
Spoiler:
A couple things that seemed... off. (Or, could be bad translations.)
Ep. 22 - Zombies at the start of the episode with no reason where they came from (which isn't explained until the very end) and no buildup towards that point in the story.
Ep. 22 - Holy Batman at quality inconsistency! Apparently Noa and Kiefer got breast implants in a span of a few episodes.
Ep. 23 - Was Ferris joking that she and Ryner would get married after they finished that mountain of paperwork? She seemed pretty serious about it though.
Unless I missed a marriage proposal somewhere around there.
Fullmetal Alchemist Brotherhood had better consistency in its story. You know where and when those Mannequin soldiers are created, which seems rather similar to those zombie-like humans used by Sion.
Wikipedia helped explain a few things but I guess it's better to read the light novel if I can find it translated.
Oh, one more thing... Ferris is awesome. Hopefully she and Ryner end up together, they seem a better match than him and Kiefer.