Accidental Aesop: Most people who see Grave of the Fireflies take an anti-war message away from it. According to Isao Takahata, the director of the film, that wasn’t what he was going for at all. This is explained below.
A mass-scale example, as Isao Takahata wanted the viewers to think that Seita was being an overly proud little boy for not simply apologizing to his aunt and asking to move back in. The majority of the audience, needless to say, saw him as one of the biggest victims in cinematic history — partially due to the lack of Jerkass moments compared to his aunt.
It looks like aside from pride, there's the very pragmatic issue that his aunt was struggling to take care of Seita and Setsuko, and with the newly decreased rations they would have imposed on everyone beyond their abilities.
Grave of the Fireflies "enjoys" a reputation as one of the saddest animated films ever made – one of the saddest films ever made, period – and there's no shortage of people who refuse to watch it for that very reason.
According to legend, back in the 1990s, an anime club in Australia scheduled both Grave of the Fireflies and Windaria at the same meeting. The screening schedule was changed at the last minute for fear that club members would end up slashing their wrists in the car park.
Glurge: Bennett the Sage and some other critics have accused the film of being this, essentially exploiting the tragedies of World War II in order to guilt 1980s youth into falling in line and being more like their parents’ generation.
The ending is meant to be at least somewhat uplifting, as a clean, happy Seita and Setsuko look down on the modern, rebuilt city of Kobe. The only problem is, this is the Kobe that existed before the Hanshin-Awaji Earthquake of 1995. The movie itself is tragic, but if you happen to have lived in the area when the earthquake happened (or lost a relative/loved one, which was not uncommon considering the number of deaths), that’s an extra - albeit unintentional - punch to the gut.
Seita's death at the end of the film becomes a whole lot sadder not only for Akiyuki Nosaka's death from heart failure in December 2015, but also for the character designer/animation director Yoshifumi Kondo's death from an aortic dissection in January 1998.
Hype Backlash: Some viewers consider the film's intentions and its emotional manipulation to be bordering on outright Glurge. Bennett the Sage said in his review that telling a sad story is not always the same as telling a good one.
It Was His Sled: Seita and Setsuko end up starving to death is the most well known thing about this movie. The former mentioning his death is the movie's opening line.
Grave of the Fireflies has been lauded by many as one of the greatest anti-war films ever made, and has gained fans in anti-war movements due to its unflinching depictions of the cruelty and barbarity of war. However, while he is no fan of war, Takahata explicitly stated on numerous occasions that Grave of the Fireflies is in no way, shape, or form intended to be, nor should it be taken as, an anti-war film.
There are those who see the film as a kick in the pants to the youths of 1980s Japan, showing them the horrors their parents and grandparents went through, and that they ought to be more grateful and quit being delinquents. In reality, Takahata has openly stated his loathing for Imperial Japan and how their conformist regimented society helped drag the country into World War II.
Narm: Setsuko's voice in the 1998 English dub. Corinne Orr is a veteran anime voice actress, with her first credit being Speed Racer in 1967. However, it's obvious that Orr was trying too hard to sound like a 4-year-old, and it ruins some of the more dramatic scenes. While her voice in the 2012 dub isn't perfect, at least Emily Neves has a lot of experience voicing young girls.
Nightmare Fuel: Seeing your mother (or anyone close to you for that matter) horrifically burned and bandaged like a mummy. Along those lines, there's the face of Setsuko in her last moments. Both are this in horribly heart-twisting way.
Some Anvils Need to Be Dropped: The message Takahata wanted to convey is that we need to be able to empathize with people even during the most trying times. Failure to do so destroys lives.
Squick: In the original short story, since Seita is deprived of all female contact and Setsuko has to mature really quickly, his and his sister's relationship develops Brother-Sister Incest undertones.
Stoic Woobie: Seita, who is proud, courageous, and remains impassive in all but the most desperate moments.
Values Dissonance: Japanese audiences are for more likely to see Seita in the wrong for not apologizing to his aunt, in line with Japanese values of familial piety. Western audience are fair more likely to see her as an Abusive Parent, and Seita's running away, if still mistaken, at least more understandable.
Due to the Animation Age Ghetto and the fact that it was accompanied by My Neighbor Totoro during its theatrical run in Japan, this has shown up in the kiddie section of some American video stores. Not good. It was also shown at the Chicago International Children's Film Festival.
On Netflix, this movie was listed in the "Kids’ Anime" genre. Fortunately, this is no longer the case, and the description on the website even says "[Seita and Setsuko] come to the somber conclusion that they can neither escape the hardships of war nor find enough food to survive."
"Suggested 3 Up" is on the back of the cover for Central Park Media's second DVD release. It does say "parental discretion advised", but that's rarely followed. The original Central Park VHS contains the description "Suitable for Most Audiences".
Averted in the case of the Australian DVD release, which is rated M: recommended for audiences 15 and up.
In Germany, it has an age certification of "6 years and older". The reason given by the FSK? "Children do not see the connection between the war suffering and the deaths by hunger. For them the loving care of the boy for his sister is in the foreground ... although she dies in the end."