The visuals of Alien Nine are spectacular, and almost at a level of quality I would consider to be worthy of a feature-film status. There's a great amount of attention to character proportions as the style this anime set out for is rarely ever carried out a notch below the ideal level. There's some inclusion of cgi elements as well, yet I would consider these additions as some of the best cgi inclusions I've ever seen in any anime. Quite surprising when taking into account that this OVA series was released in 2001. An odd amount of high budget went into this peculiar piece of work, as the cgi fits perfectly along with the spectacular two-dimensional art. The direction is also fantastic with interesting angles and visual styles.
While I doubt many would argue that the animation of Alien Nine is not too notable, the art style is another thing to consider. The art style is generally normal, with the characters being drawn with very curvy heads similar to more child-oriented shows, yet the ears of the characters are drawn with far more detail and scaled to a larger size. It's understandable that many people would be instantly turned off by this art style, but the more anime one sees along with many different art styles, the more one might become accepting to peculiar styles. This series would certainly require some acceptance of variety, some tolerance, and some will to see odd things since the story itself would also require such traits to be at all enjoyable.
The setting of Alien Nine is questionable as to what it's comparing itself to, if anything at all. As Evangelion is easily comparable to mecha series and Madoka Magica is easily comparable to magical girl series, Alien Nine seems to sit in its own element. There wasn't any key element I noticed that directly made me feel that Alien Nine was deconstructing a certain genre or series type, but the opposing styles of it along with its developing, unorthodoxed weirdness made it still feel as though it was. The story would be more similar in presentation to Madoka Magica, as young girls are place in positions where they practically gain superpowers to fight off danger. However, soon the elements of Alien Nine morph into the extreme that would correlate better with that of Neon Genesis Evangelion. There are even some paralleling moments in both Alien Nine and Evangelion that those who seek out to view both will likely notice.
Alien Nine begins as a school, superpower anime about school girls protecting their campus with gifted, super abilities. The main character is extremely shy and fragile, but is placed in a position where she will have to go into danger to fight off aliens from her school's campus. That's the introduction for the beginning, closely relating to the OVA's opening which likely intentionally gives the series a more innocent atmosphere to start out with. Even during these more conventional moments in the anime, the music and some visual cues foreshadow a coming change.
The music in Alien Nine is unique and, although it may sound dry or lacking in budget at times, an intentional style slowly emerges that makes the whole audio experience memorable. The music will play in a way that is almost fitting to the starting presentation of what the anime is, yet there will always be an odd pitch and tone to it, almost like a record in a record player slowly shaking off-center. Alien Nine did extraordinarily well in its audio aspects for the style it carried out.
Alien Nine is more of an experience than a story, and it should be noted that the experience is incomplete. This OVA series also serves more as an advertisement to the mangas by its chosen end-point as it's completely unsatisfying and in many ways not even able to be considered an ending at all. However, from the quality and intrigue found in Alien Nine, the series is one of the top that needs to either be remade or have a sequel made. For those who like mangas, they will likely deliver some of the experience, but the audio and the quality will be sorely missed when moving on. The characters and art style are claimed as annoying in many places I've visited, but if one remembers this is an experience, things may start to feel more fitting in due time. The characters are shallow for the most part, but stylistically so. The whole criticism to that would fall very close with those of the character Shinji in Evangelion. Depending on how people felt towards that character and story, those people will likely feel the same to what Alien Nine has to offer. Overall, Alien Nine is a memorable and entertaining OVA series even in its incomplete state.
