Shame is a tough film. Bergman talks about the influence of events in Vietnam and the wish to depict the effects of war in an uncompromising way. He is very hard on the first half of his movie, which he suggests does not fulfill this purpose and could have been drastically cut down. I think the before and after is quite useful, however. The film begins with a day in the life of the central couple, the bits of civilization (music, wine, philosophy) they treasure, and the petty disputes that disturb their tranquility (Eva wants children, but Jan is a sensitive soul who thinks it's inadvisable with a war on).
The second half shows this marriage break apart under the strain of totalitarianism, and the terrorism it fosters. A local warlord (and former friend) renders the couple his servants, and their resentment towards him is channeled between each other. Eva talks of being a player in someone else's shameful dream. She is forced to film a propaganda piece for the resistance, and later on the warlord pays her to have sex with him, which crushes the life out of her.
Jan, on the other hand, is hardened by that incident. The one bit of comedy in the film comes in the first half when, in the midst of fleeing bombardment, Jan tries and fails to shoot a chicken point blank so that he and Eva will have something to eat. In the second half, Jan is forced to reenact that experience, but this time the warlord is in his sights and it's deadly serious.
The fragility of civilization is an obvious theme – and the film is rather good on the way peace depends on trust, both personal and political. Less clear cut is the suggestion that the microcosm of the central marriage somehow mirrors the political conflict taking place in the outside world. Jan is yet another self-centred intellectual used by Bergman to punish himself, and here the self-laceration goes into the fear of the horrors he is prepared to commit to survive. Eva is the beautiful, simple-minded and kind-hearted woman who only wants children and gets trampled once society breaks down. Although she is patronised by her husband (and to some degree Bergman as well) she is arguably the more courageous, in that she cannot stomach the things Jan has to do to preserve their lives. In the end those compromises are futile, and perhaps it would have been better to die with more dignity.
Dreams of a better life bookend the film. It opens with Jan recounting a dream of the war being over and the couple continuing with their civilized lives. It ends with Eva describing a surreal dream in which she and her imagined daughter watch a garden being torched by warplanes, and she tries to remember something which makes her start crying. The couple's dreams are soiled by the violence around them, to the point where they become unable to hope for something better. But the shameful dreams of the oppressors, which have created this situation, remain mysterious.
Shame explores the effects of the war very well, but it doesn't delve into its causes. That, for me, is the real weakness of the film.