- Adaptation Displacement: the anime is decently well-known in the west due to premiering on Toonami during its prime with a sizable marketing push, but the manga is essentially forgotten, never translated, and hard to find information on, to the point that even its Wikipedia article is almost entirely about the anime adaptation.
- Alternate Character Interpretation
- Zorndyke. Dear lord Zorndyke.
- Hayami and Mutio, and whether their romantic relationship was one-sided. Mutio is clearly smitten with Hayami, but Hayami didn't seem to return these feelings, beyond simply being concerned for her safety.
- Awesome Music: The entire soundtrack, performed by (unknown outside of Japan) funk/jazz group The Thrill. Released on CD in Japan.
- Big-Lipped Alligator Moment: The seemingly Perfect Pacifist People introduced towards the end given how they pop up during a war of genocide.
- The scene in episode 2 where Verg starts licking one of Mutio's sisters during his Villainous Breakdown, and then Mutio herself when he finds out that she made physical contact with a human during the battle. Both are done in a very disturbing way.
- During the scene in episode 1 where Hayami saves Mutio and brings her into the water, Mutio stares at Hayami before emitting a sonic cry of some sort. Why she does this is not explained, and we never see her nor any of her sisters do this in the rest of the OVA.
- Cult Classic
- Ensemble Dark Horse: Mutio, for her unique design, passive nature, and relationship with Hayami.
- The Cat Girl that reads poetry throughout the third and fourth episodes has garnered some attention from fans, even though her total screentime in the anime is very brief.
- Harsher in Hindsight: Seeing the city of Tokyo, flooded and in ruins, can seem unsettling after the earthquake and tsunami that hit Japan in 2011.
- Hilarious in Hindsight
- Hayami asking Kino if he can smoke while they're repairing Blue 6 can be this to American viewers, given that the U.S. Navy banned smoking on submarines in 2010.
- Mutio is a Minion with an F in Evil that works for a Psychopathic Manchild Darth Vader Clone with daddy issues. Then she soon discovers one of her comrades was killed in action, is subsequently given a hard time by one of her superiors, pulls a MookFace Turn, saves the life of a man that is supposed to be her sworn enemy, and seemingly falls in love with a protagonist that used to make a living as a scavenger before being flung into a war that they wanted no part of, and then eventually goes back to confront her former superior that once gave her a hard time. Sounds an awful lot like Finn, doesn't it?
- Zorndyke, the antagonist of this story, is a genocidal Well-Intentioned Extremist with philosophical views on his work and genuinely believes he is doing the right thing. His plan is to destroy a significant portion of the world's population with the intent to make it a better place to live in for those that are left. He has two children: One is a daughter (the unnamed Cat Girl) that he loves and treats with the utmost respect, while the other (Verg) is an angry, murderous cyborg that wants their father to give them the same love and respect, but isn't getting any of it due to their father constantly underestimating their abilities. Twenty years after this anime aired, we would see this same character dynamic again.
- It's Short, So It Sucks!/Too Good to Last: A common critique of the show is that while it has an interesting premise, characters and lots of potential for both of those to be developed the fact that it was only four episodes long kind of made that impossible.
- Moe/The Woobie: Mutio. If her generally adorable appearance/personality doesn't make you want to hug her, the Trauma Conga Line that she goes through definitely will.
- Suspiciously Similar Song
- They Wasted a Perfectly Good Character:
- Katsuma. The man who was the first to try reaching out to Zorndyke for a peaceful solution barely has any screentime, doesn't even accompany Hayami and Kino on their mission to confront Zorndyke, and the fact that he was mutated into a chimera instead of being outright killed is unexplained and would certainly have warranted a sub-plot of its own...had the OVA been more than four episodes long, that is.
- Mutio, after having a prominent role in the third episode, is brushed to the side after the first scene of the fourth episode. And despite characters on both sides making a big deal about her and Hayami's relationship, it ultimately becomes inconsequential to the story's conclusion, and is never mentioned when Hayami confronts Zorndyke.
YMMV / Blue Submarine No. 6