Two veteran filmmakers, Sidney Lumet and Woody Allen, had new films in the Festival, and each in his own style presented dark views of what human beings can do under certain circumstances. Lumet in “Before the Devil Knows You’re Dead” delves into film noir with a tale of two sons who set out to rob their parents’ jewelry store, with consequences that flow out of the plan. The brothers are played by Ethan Hawke and Philip Seymour Hoffman. Albert Finney and Rosemary Harris are cast the parents.

Lumet continues to be in fine form, able to build tension as the work escalates into a New York version of Greek tragedy. He knows how to meld background and events for maximum effect, and the moral decay depicted provides a jolting comment on how pressures and greed can spiral into the unthinkable.

Writer-director Woody Allen also approaches evil acts, but with a lighter touch in “Cassandra’s Dream,” which makes one think of his “Crimes and Misdemeanors.” This film is set in England, and although serious in its observations of human behavior, there is an underlying black comedy touch related to the unexpected turns and outrageousness of the situations involving what some are prepared to ask of others and of what people will do by rationalizing the frittering away of their morality.

In this case two brothers agree to undertake a deadly task demanded by their well-heeled uncle as repayment for his helping the family financially. The family portrait is itself droll, and the characterizations are amusing, with Colin Farrell and Ewan McGregor as the brothers and Tom Wilkinson as their manipulative uncle visiting from Hollywood.

“Atonement,” based on the popular novel by Ian McEwan, deals with how lives are shattered by the false accusation of a young girl, who later regrets the havoc she has wrought. But saying one is sorry comes as too little and too late. Director Joe Wright and screenwriter Christopher Hampton have created a memorable film that is rich in mood and solid acting, as well as broad in scope.

Keira Knightley stars as Cecilia, who has repressed emotions for James McAvoy as Robbie, who is beneath her class and only the son of one of her well-heeled family’s servants. Her 13-year-old sister Briony, played by Saoirse Ronan, lives in her fantasy world and is jealous of Cecilia. She makes a despicable false accusation that throws everyone into turmoil.

The film’s early part starts in the mid-1930s, and the story continues into World War II. Accordingly, there is substantial atmosphere through settings, costuming and events, and the cinematography by Seamus McGarvey contributes strongly to the atmosphere, thereby giving the film a sweep against which he individual stories are developed. “Atonement” is a most impressive achievement.

The Festival’s opening night film, “Fugitive Pieces.” is also based on a book, a novel by Anne Michaels. Jeremy Podewsa directs from a screen adaptation that he wrote. The deep emotional problems in this work stem from events during the slaughter in World War II. After Jakob, a seven year-old, sees most of his family killed by the Nazis in Poland, he is discovered by a Greek leading an archeological dig, Athos, who is played by Rade Sherbedgia. Athos takes the lad under his wing, and after smuggling him back to Greece, becomes a surrogate father to him.

The film flashes between its present and Jakob’s memories, haunted by the question of what happened to his sister. Robbie Kay is terrific in the memory scenes involving Jakob as a youngster. As an adult, the character is played by Stephen Dillane in a superb acting job of a difficult role marked by repressed emotions. His efforts at a personal relationship with Alex (Rosamund Pike) are troubled because he is not ready to open up despite her eagerness to be close to him. But eventually he finds another woman with whom he can develop a relationship, this time ready to expose his feelings and emotions.

The screenplay shifts an early portion of the book to the end of the film with results that can be debated. That issue aside, “Atonement” is a mature, thoroughly engrossing film that touches on the nagging issue of the damage that persists as a result of the Holocaust even after the lapse of so much time.

Personal trauma of another sort is at the heart of “Reservation Road,” directed by Terry George from a screenplay he wrote with John Burnham Schwartz based on Schwartz’s novel. How a family deals with the sudden tragic loss of their young son and how the hit-and-run driver deals with the battle between his wanting to avoid responsibility and his conscience are the problems dealt with in this sensitive, disturbing film.

The cast consists of Joaquin Phoenix and Jennifer Connelly as the bereaved parents, and Mark Ruffalo as the perpetrator, whose ex-wife is played by Mira Sorvino. All are excellent in their roles, and the film is emotionally touching at various times, and it also implies a hypothetical question: How would one act in such circumstances?

Yet more personal trauma fills “The Girl in the Park,” a first feature by David Auburn, who also wrote the film. It contains a strong performance by Sigourney Weaver as Julia, who is trying to deal with a terrible event in her life. One day while she is in the park, when she turns her attention from her young daughter for just a bit, she then finds the child has disappeared. No trace of her has been found, and Julia is desperately going through life with the hope that eventually she will be located.

One day Julia befriends Louise (Kate Bosworth), a young woman who has been shoplifting. The drifter takes advantage of Julia, but the desire to be mother to a daughter, compounded by her fantasy that Louise could turn out to be the daughter she has lost, results in a close relationship blossoming. Julia’s son, who is soon to be married, wants to bring her down to earth, but by this time Julia is an emotional wreck who needs to snap out of the world she has built for herself. The film also becomes important in its portrait of Louise, who is desperately in need of connection and straightening out her life.