Mike Collett-WhiteReuters
September 5, 2011, 12:54 p.m.

VENICE, Italy (Reuters) - The Venice film festival has largely lived up to its billing so far, providing a steady stream of A-list actors on the red carpet and a lineup of movies which has pleased most critics.

As the world's oldest film festival hits halfway Monday, an adaptation of John Le Carre's "Tinker, Tailor, Soldier, Spy," George Clooney's political thriller "The Ides of March" and Roman Polanski's comedy "Carnage" lead the charge for the coveted Golden Lion for best picture.

They are among 22 movies announced so far, soon to be joined by a 23rd "surprise" film unveiled Tuesday, vying for top prize, which is announced Saturday.

Although festival juries are notoriously difficult to second guess, an informal poll of critics published by trade magazine Variety puts Carnage marginally in the lead, but ratings have been generally strong.

Booing at the end of press screenings is common at film festivals, but there has been little this year, suggesting a happy ending to festival director Marco Mueller's term in charge.

Carnage is Polanski's adaptation of stage play "God of Carnage," and stars Kate Winslet, Jodie Foster, Christoph Waltz and John C. Reilly in a critique of bourgeois values set in real time in a single location.

Waltz's constant Blackberry interruptions, barbed exchanges between two New York couples and in particular Winslet's "vomit scene" had journalists laughing out loud.

Polanski would not be able to collect his prize should he win, facing extradition to the United States where he is still wanted for sentencing for a crime committed in 1977, but victory would be generally popular.

Tinker, Tailor, Soldier, Spy, which premieres Monday, also emerged as a strong contender, with early reviews glowing for the melancholic adaptation of Le Carre's 1974 classic.

Gary Oldman takes on the central role of George Smiley, famously played by Alec Guinness in a television series, and Colin Firth and John Hurt also star.

"The big-screen version of John Le Carr's 1970s spookfest is hot favorite for the ... Golden Lion," said Jason Solomons, film critic for the Observer weekly.

"Just how Swedish director Tomas Alfredson got under the skin of British behavior so intuitively is remarkable."

NO SHAME IN "SHAME"

Clooney got the 11-day cinema showcase off to a strong, starry start with opening film The Ides of March, a thriller set in the world of American politics in which he, Ryan Gosling and Philip Seymour Hoffman appear.

And Steve McQueen, a British artist-turned-director, got what many consider the performance of the festival so far from Irish actor Michael Fassbender as a sex-obsessed New York professional in "Shame."

"Fassbender...might already have the Coppa Volpi (for best actor) in his pocket," wrote La Stampa daily.

Oldman also won praise for his nuanced portrayal of Smiley, and among female leads, Aggeliki Papoulia in Greek tragedy "Alps" and Keira Knightley in David Cronenberg's "A Dangerous Method" impressed.

Alps and Italian entry "Terraferma," tackling the hot topic of immigration, had plenty of admirers, but "That Summer," starring Monica Bellucci, was poorly received.

Outside the main competition, Madonna presented "W.E.," her stylish re-telling of the story of American divorcee Wallis Simpson and her relationship with King Edward VIII.

Andrea Riseborough was singled out for her role as Wallis, but overall the movie got a lukewarm critical reception.

Steven Soderbergh brought with him a stellar cast in "Contagion," a slick examination of the spread of a deadly disease and the global panic it causes.

Matt Damon, Gwyneth Paltrow and Laurence Fishburne all hit the red carpet, as did Hollywood veteran Al Pacino who was honored with a lifetime achievement award.

At 71, the "Godfather" actor drew big and noisy crowds on Sunday, as he presented his documentary "Wilde Salome."

(Additional reporting by Silvia Aloisi, editing by Paul Casciato)