"A pulpy page-turner in its original incarnation as a huge international bestseller has become a stodgy, grim thing in the exceedingly literal-minded film version of The Da Vinci Code," wrote Todd McCarthy.

Lee Marshall of Screen International agreed.

"I haven't read the book, but I just thought there was a ridiculous amount of exposition," he said. "I thought it was plodding and there was a complete lack of chemistry between Audrey Tautou and Tom Hanks."

Lou Lumenick of the New York Post was far more upbeat:

"Ron Howard's splendid The Da Vinci Code is the Holy Grail of summer blockbusters: a crackling, fast-moving thriller that's every bit as brainy and irresistible as Dan Brown's controversial bestseller."

Critics say the controversy surrounding the film, and the fact more than 40 million people have bought the book, will ensure a strong box office performance, but they believe word-of-mouth is likely to hit sales later on.

The movie industry will be watching The Da Vinci Code particularly closely after the first two summer blockbusters -- "Mission: Impossible III" and "Poseidon" -- stumbled.

Howard had some advice for those who objected to the story.

"There's no question that the film is likely to be upsetting to some people. My advice is ... to not go and see the movie if you think you're going to be upset."

Ian McKellen, an openly gay actor who plays Leigh Teabing in The Da Vinci Code, tried to make light of the controversy.

"I'm very happy to believe that Jesus was married," he said. "I know the Catholic Church has problems with gay people and I thought this would be absolute proof that Jesus was not gay."

The opening ceremony and Da Vinci Code premiere kick off 12 hectic days of screenings, interviews, photocalls and partying in Cannes, the world's biggest film festival.