The story is set in the distant future, featuring space ships, war, a third gender, and super powerful aliens known as Gauna. The Gauna in particular is where the story reaches it's peak; these super-powered aliens which resemble machines are incredibly deadly and constantly evolving. You can really feel the fear the characters do when their squads are being cut down like butter, having to watch their comrades gruesomely die screaming.
The third gender that is introduced is also one of it's finer ideas. This hermaphroditic third gender can act as either male or female, depending on what Sidonia needs to bolster it's population. But like the series as a whole, the idea is never entirely fleshed out. There is merely one episode dedicated to this fact, and it's around one of the main characters, Izana. She falls in love with the main character and ultimately decides to become a girl, which is fine in it's own right, but what being a third gender is like never explored enough, simply glossed over. Sexual identity, a big topic today, is never brought to terms with the third gender. It's unfortunate that the idea wasn't executed as well as it should have been.
The characters in general aren't unlikeable per se, but neither are they particularly interesting. Izana's identity as a third gender is brushed aside after one episode. And every character has a bland design, looking nearly identical to everyone else and having vague motivations. The three protagonists all have short dark hair, with similar eyes and statures (including Izana). There's the general chick whom has dark hair and wears a mask, with some vague history of a grudge or something and a silver haired prodigy of sorts whom is jealous of Nakate, the main protagonist, for taking a legendary ship or something. There's also an old repair guy whom gets a few lines towards the end of the series, the main protagonists grandpa who's mentioned several times for some sort of history and training Natake. A group of old guys whom run things and probably know stuff. Everyone amounts to nothing more than a bunch of vague "somethings."
That only scratches the surface as to the problem with the characters. Other than the fear factor the Gauna emanate, you'll be asking yourself "Why should I care about these people?" Most of the story and characters give that impression regardless, and it's mostly due to the perplexing elements that are never told or explained properly. Who? Why? When? How? These are questions which are too often never answered.
The art is usually fantastic in it's presentation, even if the "high speed" scenes can be difficult to follow sometimes, it's usually good and battles often look slick. My only complaint, other than the aforementioned boring character designs, is that the majority of environments are bland and uninteresting. That may work for a series set in modern day Tokyo, but not one that takes place in the distant future in space. The sound is okay, usually- things that shoot go pew, things that blow up go boom. Yet neither are there any particularly memorable tracks or songs. I guess the patriotic opening was decent.
The story harvests a bunch of good ideas together. Unfortunately, few of these ideas ever become ripe enough to be worth indulging. It becomes apparent by the eighth episode that it won't ever be anything more than a mishmash of several good concepts, and in the end it fails to succeed at even a few basic, essential ones. You'll finish it befuddled, wondering what could have been. By the following week, you'll have forgotten everything about it, forever referring to it as "that space anime I watched one time."
