This is a nuanced film that explores human nature as it reveals itself in adversity, whether that ensues from a random accident or a state like poverty. The main theme is a study of how personal morals and the feeling of responsibility can differ between people and drastically affect their behavior and emotional state.
The main character, who is by all accounts a moral person, is the harshest critic of himself, and feels the weight of responsibility to the extent that he is self-destructive, or even causes more pain to others. Other characters range from being negligent, to pushing blame on others in a careless way, to rationalizing, or to recklessly promoting their own self-interests by endangering others. Almost every character shown makes a decision that reflects their moral values and how seriously they are committed to them, although their choices are determined by factors out of their control. Even without bad intentions, their actions can have dire consequences. The greatest success of the movie is that the viewer must keep wondering whether the characters' decisions can be justified - what is right or wrong is rarely clear.
Despite the sad plot and the difficulty of the topic, the reason why all of the above results in an outstanding movie is the excellent screenplay, the brilliant work of the director and the great performances by the actors. This movie deserves to be watched and carefully contemplated upon.