Arpeggio of Blue Steel is based on the eponymous manga by Ark Performance, so it does not have any direct connection to Kantai Collection, a “character card battle game” with a similar premise which is getting its own anime adaptation later in 2014. (That being said, there have been some cross-overs between the two, such as some illustrators from the latter working on end cards for the former and a special Arpeggio-themed event taking place in the latter in late December 2013, and the fact that the source manga for the former came out four years earlier suggests possible inspiration.) The concept behind both of them – that WWII-era naval ships have avatars that are cute girls or young women – is not a big stretch, as it could be looked at as part of Japan's well-documented continuing attempt at moefication of everything. Numerous precedents for weapons or even ships which turn into or represent as girls or young women also exist in anime, and as one of the Mental Models points out herself when asked about why the Models are all female, naval ships have traditionally been referred to in feminine terms. Hence the underlying concept is not a problem.

What the series does with the concept is another story. The set-up is laid out well enough by the first episode, but the story otherwise spends very little time establishing the foundation for its cast. Only a relatively short flashback shows how Iona and Gunzo met, and nothing is shown about how Gunzo's rather oddball set of friends at the military academy ended up crewing the I-401; indeed, the story reveals almost nothing about them, such as why one character always wears a full face mask. That the series never does much of anything with such a potentially interesting-looking bunch is its biggest failing, but clearly its priorities focused much more on the high-powered naval battles and the interactions of the assorted Mental Models. The writing also seems more concerned with setting up harem-like circumstances, albeit with one of the Mental Models being head over heels for Iona, rather than Gunzo. The harem is slow to develop, though, as for most of the series Iona is merely absolutely loyal to Gunzo and does not bring emotion into the picture. A further distraction is brought in by the arrival of the child genius character and her emphasis in a two episode mid-season arc.

The series does have its moments, though, and most of those come in the final third. Prior to that point what little storytelling meat the series has comes primarily from the interactions of the Mental Models with each other, especially in the cyberspace setting where they gather. Much of that involves the ladies trying to figure out why the I-401 has become such an ornery foe with a human commander and debating how much introducing emotions into the equation is a corrupting influence. Seeing the way the ladies who have direct contact with humans gradually start appreciating them is fairly standard stuff, though the way that Takao, Haruna, and Kirishima change when Iona, who is been in contact with humans the longest, does not is an interesting contrast. When she finally does start to open up a bit and show some real emotion concerning Gunzo, which coincides with the hairiest battles yet for the I-401 and her allies and the gradual meltdown of Asian Fleet of Fog leader Kongou, is when the series hits full stride. As a result, the last third of the series is a considerable improvement over the previous two in almost every narrative respect.

And of course the naval battles get plenty of screen time. The Fleet of Fog ships are, indeed, fundamentally designed like their World War II counterparts, but their advanced technology (missile launchers, defensive energy fields, supergravity cannons, nanotech repair capabilities) is many steps beyond. Thus the naval battles are as much science fiction showpieces as tactically-intensive affairs, and the final battle goes a little overboard in that regard. The animation of the ships and battles depends very heavily on CG, but viewers not overly bothered by that should find some involved, well-animated, and fairly intense battles which are sometimes waged simultaneously on physical and virtual levels.

The pronounced CG effect can be seen in other aspects of the series, too, including (in some places) the character rendering. Scenes where this is most evident have characters moving in stiff, almost mechanical fashions and have a more artificial sense of life, though fortunately this effect is not omnipresent. Stronger are the character designs, as each of the Mental Models has her own distinct look – save, of course, for Iona's sister ships, the I-400 and I-402, whose Models naturally form a set of identical triplets with Iona. Fan service is limited and mild when present; one of the Models in undies in part of one episode and a few others in swimsuits during a beach episode is largely the extent of it.

The music for the series is fitting but never a stand-out. Opener “Savior of Song” suits the series well and sets the tone appropriately, while three different closers are used over the course of the series, to varying degree of success. The tone of the regular one sometimes seems a little off compared to the episode contents. The Japanese dub is most distinguished by Mai Fuchigami's deadpan delivery as Iona and the odd and somewhat annoying speech affectation given to Hyuga by Saki Fujita (Ao in the Yozakura Quartet franchise). Curiously, different seiyuu are used for voicing Iona's “sisters.”

The last few episodes of Arpeggio of Blue Steel are strong enough to balance out the much weaker start and deficiencies in the set-up, but one has to wonder if this series might not have fared better with another episode revealing more about the crew and how it came together. (Perhaps an OVA episode could fill in this gap at some point?) The story also has more room to go places at the end, although where it could go is tricky since some of its later content does deviate significantly from the source manga. Ultimately the series seems to be playing equally for military otaku, harem series fans, and science fiction fans, and it puts it all together just well enough to be entertaining overall.