A film about one man, alone, thrown back on his own resources.
If you consider a film which focuses on a single character, mostly in a single location, with minimal dialogue, then you might expect a narrative of great emotional intensity, but you probably would not expect the tension and immediacy that this film also has. I came across it by chance, and stayed glued to the screen, spellbound.
This is not a "Colditz"-style story, with its emphasis on comradeship in adversity, and attempt to see both guards and prisoners as individuals, with human frailties.
The hero is held in solitary confinement - that is why there are so few other characters. The enemy are faceless oppressors; we do not see his interrogation, the torture is evident from the condition in which he is returned to his cell.
The absolute emptiness of his cell is mirrored in the sparse, bare style of the narrative. It has the courage to disregard all extraneous concerns and concentrate on its single theme - the amazing resourcefulness and courage of a single individual, under almost intolerable conditions.
Watching this film is an intense, compelling experience, but ultimately uplifting, as it demonstrates what a human being is capable of.