This isnt one of the best series I have seen, but it is definately of average quality. The biggest shortcoming of Avenger is that this series should have had more episodes, somewhere around 24. They try to stuff too much in just 13 episodes, diminishing the overal quality quite a bit.
The story in itself is pretty well done, but should have had more episodes. While I disagree with people saying that this title is confusing when the story progresses, I think they should have put more emphasis on certain story elements. I dont mind a few things kept unexplained (it is fun to keep guessing what it could have been), this story just leaves too much open. In general you can divide this story in three parts, the story about mars itself, the story about layla and the story about Nei. Of these three, the only one that developed well was Laylas story, the other two (especially the part about Mars) are not developed well enough.
The overal animation was done very well, with fluid animations and very detailed characters. I havent been able to spot many (of not none) reused frames, so thats a plus. That which I especially liked, were the background designs. At first it seems that backgrounds are reused to the death, but this is not the case. The image they want to create is that people are living on a desolate planet, with hopes near to zero of survival. That image is created very well.
The opening theme, by Ali Project, is upbeat and begins with a quick, rigid, high musical note, bringing chills and an exciting distinctness from the same old melody that us otakus hear all the time. The ending is very much that way too, but sometimes it reminds me of a nursery rhyme I once did, so I didn’t listen to it that much. Background music is great. I remember a multitude of times I would listen to the bg music more than the dialogues between characters…the music has much more potential than the story.
While I dont know whether or not I would recommend this title, I actually enjoyed it a bit while watching it. It is not the best title around but it was still a nice way to kill my leftover time.