"We decided not to deal with the economic crisis but rather to confront the crisis of values," the director of Alexandros Avranas said after the screening.

Festival director Antonio Barbera said the films in competition, which will be judged by a panel headed by veteran film maker Bernardo Bertolucci, shows a dark and violent reality.

Themis Panou, who plays the tyrannical father in , said he had to draw on Greek tragedy to help him play a character who was unlike anyone he had ever known.

"I think many men thought of sleeping with their mothers. Oedipus is not a chance event, and this is how I built my character," Panou said.

Sordid sex and violence infuse family relationships in Philip Groening's and David Gordon Green's , which also had their premieres at the festival.

The character of Wade in , who shamelessly exploits his son and daughter for money, is "a man whose moral bankruptcy knows no limits", critic David Rooney said in trade paper the .

Lester Ballard in James Franco's , on the other hand, is driven so far out of his mind and society that he seeks solace in necrophilia, and is even portrayed with sympathy.

The grisly sex scene is played "with a measure of real tenderness, which serves only to render the overall tableau all the more ghastly", critic Justin Chang said in trade publication .

In the shock of the 11-year-old's suicide initially contrasts with the bland expressions on her family's faces and the stock images of a birthday party - complete with paper hats and luridly iced cake - in a nondescript apartment.

Reni Pittaki, whose character in is dumbly complicit in child prostitution for much of the film, likened the role to one from classical theatre, which tried to tell universal truths. "I saw in this woman the archetype of a tragedy, of a drama, of a Greek tragedy."

Among films still to debut at the Venice festival before it ends on September 7, are , a potential comeback for cult hero Terry Gilliam, and , a documentary about ex-US defence secretary Donald Rumsfeld.