Redemption in the Film vs. the Novel
Last Exit to Brooklyn is one of the better adaptations of a novel to film. Like any, it leaves out some things and adds others, but among these is one crucial difference - no matter how brutal much of the film is, it suggests redemption for at least some of the characters, unlike the novel.
The film falls into the trap of turning Tralala into the cliched "hooker with a heart of gold," in the final scene where she thinks about the serviceman's letter and comforts the infatuated Spook. In the novel, Tralala was every bit as cold, inhuman, and heartless as her tormenters. She was beyond redemption and was basically left for dead in her final scene effectively thrown away with the rest of the trash.
The portrayal of Harry Black was mostly in keeping with the novel, except for one thing. Lang's Black displays considerable strength and courage during the fight with the strikebreakers, while in the novel, he's a complete coward behind all of the bravado, staying on the sidelines while others in the union get their heads smashed in.
Perhaps the biggest difference is that the film ends on a positive note - the workers triumph and go back to a redeeming, happy family life. The novel ends in a tenement building where the sleazy main character leaves his wife and family to live in squalor while he buys accessories for his new car.
The implication seems to be that you can write a novel about irredeemable characters, but you can't get away with making a film with this sole theme.