Throughout most of the novel, Billy is living is life in reverse and also in fast forward. He is "unstuck "in time." Seeing the war movie backwards exemplifies Billy's experience of going back to World War II and re-living his captivity in the war. Just as he sees the ending of the film first, he also knows how each episode of his life will end. The fact that the movie is also about the war is important because that's where Billy always seems to finally end up during one of his time-traveling moments. This reinforces helps reinforce the idea that just as seeing a war film backwards, war itself is disorientating and absurd.