Same as the more recent "Warsaw 44", by Jan Komasa, this first Andrzej Wajda film deals with an authentic event: the collapse of the uprising of the Polish underground army against the German occupiers in September 1944.
When it turns out that a Warsaw suburb can no longer be held, Lieutenant Zadra is ordered to reach the city center through the canal system. Wajda dedicates two thirds of his film to this dramatic march, examining the various possibilities of human behavior in the face of death.
The simplest and shortest way out is to flee to certain death, a kind of suicide: a soldier who has had enough of wading and stumbling around in the stinking broth tries to escape through the nearest exit. It is guarded, however, and so the fugitive is greeted by a volley of machine guns, which immediately throws him back into the just abandoned broth, the only difference being that he is now protected from all the rubbish and poison (the Germans let gas into the sewer system!), feeling nothing.
The composer Michal, who got into this adventure only by accident, escapes into madness: he hears a melody in the distance and trills it, stumbling further and further through the canal in a circle, without himself being aware of the situation. Even friends are not recognized by him, orders to come back are not heard.
For others, the path of suffering is much harder. Ensign Korab has to drag himself injured through the labyrinth. He is accompanied by his girlfriend Stokrotka, who breathes new zest for life into him again and again. In the end they come to the river Weichsel, which promises a way out. However, an iron grating prevents them from moving forward and Stokrotka can only tell her friend about the green meadow behind the grating. It is not possible to get there, the cruel rules of the game of war prevented it.
Wajda's film therefore not only shows human behavior in an extreme situation (another one would be the merciless egoism, which, losing all respect for the life of others, is only concerned with saving one's life at all costs), it's an anti-war film too. At the end of the day, Lieutenant Zadra has to realize that he has lost his company, that he is alone, just as the war, which at the beginning still has collective features, later becomes more and more an individual tragedy.
However, "Kanal" is much more than a mere film about war; an additional dimension endows it with a parable character. The canal becomes the path of life, on which the human being, hindered by dirt and feces, jumps around badly and desperately, searching desperately for an exit. Only those are happy here who are not aware of their situation, such as the composer Michal, who has given up striving for salvation, no longer caring about the meaning and purpose of the company.
For everyone else, the struggle for survival continues, as does the search for a better life. However, the paths to reach it are blocked, like it is shown in the scene when the iron grating prevents any progress to the green meadow on the other side of the river Weichsel, comdemning the humans to the cesspool as their only living space.
