Cannes bowled over by Tilda Swinton in ‘Kevin’

She's not to everyone's taste, but Tilda Swinton has certainly impressed the critics with her latest role. "Magnificent", "formidable" and "mesmerising" are among the accolades from the critics in Cannes after the screening of We Need to Talk About Kevin, and she is already been touted for the best actress award at the festival.

Swinton plays Eva, the quietly depressed mother of Kevin, who is in prison for massacring students at his high school. The film is based on Lionel Shriver's bestselling book of the same name, which is presented as a series of letters written by Eva. Although the film unfolds differently it holds onto the narrative device of staying entirely within the confines of Eva's mind.

This can be an unnerving experience as Eva struggles alone to find an explanation for her son's behaviour. But, in what the Guardian's Peter Bradshaw calls a "skin-peelingly intimate character study", there are no answers.

Swinton, however, enjoyed the introspective role: "Words in many ways makes looking at life really complicated," she said. "This film was an opportunity to be this interior and this lonely; lack of words was if anything an easy thing."

This throbbing silence is felt throughout the film. "[Swinton] conveys every thought racing through her character's mind," says Kirk Honeycutt for Reuters.

"It's about feelings," Swinton explained. "Being a parent is like writing one long letter you never send. At the end of the day the only thing you can hear is your heartbeat."

According to Sukhdev Sandhu in the Daily Telegraph, the film is "at times a one-woman show... [Swinton's] face is hard to take your eyes off". Kenneth Turan in the Los Angeles Times agrees that We Need to Talk About Kevin is "difficult to watch but impossible to turn away from. [Swinton] has to be an early-favourite for the festival's best actress award."

For Derek Malcolm at the Evening Standard, "Without Swinton... the film might have sunk without trace under the weight of its morbid subject matter. But she is pitch perfect throughout, restrained but still forceful".

We Need To Talk About Kevin is also a triumphant testimony to women in film: Lynne Ramsey is one of only four female directors in the running for the Palme D'Or this year. Last year, there were none. ·