Steven Sheehan’s review published on Letterboxd:
'You can't exist outside the system' harsh words spoken through an anime that can be applied through the ages. There is an expected and accepted way of living. If you don't want to conform, it's your problem. There is only one way. Anything outside of that and you are an outcast, a nothing. Not even a number. The chaos of war will let even the most committed slip through the cracks, let alone those living outside the margins.
Big brother Seita perhaps represents the pride of a nation sold-out by an Emporer who led them into years of battle driven deprivation. A young man who cares deeply for his younger sister, given the responsibility of ensuring her growth and prosperity but unable to find the right path toward it. The idea of how war warps humanity and the impact on those left to sweep up its ashes runs throughout the entire film.
There is no attempt to shy away from the casualties of war, which are never those in the ivory tower directing the battle. People often failed by the system yet still willing to protect their country become cannon fodder and those left behind try to find a way of filling the gaping holes in their lives. Carcasses at the start of the film are treated as nothing more than disposable trash, the sibling's Aunt has little patience to respect Seita and Setsuko unless they are part of the 'solution'. Even the doctors have lost their sense of empathy in the knowledge that death is now almost an unavoidable certainty.
There is also no flinching from the fact that war spares no-one and in particular, it is the weakest and most vulnerable who face the darkest consequences. Japan had been left in ruins, as had the siblings relationships with adults in society; their mother and father lost to war, their aunt eventually estranged, relatives nowhere to be found in the city and farmers viewing them as little more than thieving scavengers.
Like When The Wind Blows it becomes increasingly hard to watch them scrapping to retain a sense of dignity. Children are supposed to represent the next generation and with their deaths there goes a certain amount of hope for a country needing to find its feet again. These are mature themes to channel through this sort of medium but they are told with a sincerity that stops it from becoming shrouded in unbearable despair.