An afterword at the end of the late Carl Sagan's novel Contact notes that it started as a film treatment written in the early 1980s. For several years it was a project for Australian director George Miller, but he jumped ship as the budget skyrocketed. Now, finally, Contact arrives courtesy of Robert Zemeckis and preceded by ecstatic reviews from the US critics.

At the level of plot, the film is reasonably faithful to Sagan's novel (which I read as a trainee geek back in the late eighties). Young radio astronomer Ellie Arroway (a perfectly cast Jodie Foster) is engaged in a search for radio signals from extra-terrestrial intelligence; she appears to have stalled her career by doing so, but then, dramatically, a message is received. Like most science fiction novels, Sagan's book was less about story and character (and, in fact, is pretty deficient on both levels): it was an exploration of ideas. Broadly speaking, the ideas that Sagan raise are the same ones that Zemeckis runs with. If a message was received from a superior intelligence, what would it say? And what would the reaction on earth be? What implications would it hold for, say, religious groups?

You have to give Zemeckis and his collaborators credit for tackling such cerebral material, and this certainly marks an enormous progression from last year's God-awful The Arrival. For that matter, it's also an improvement on Zemeckis' Forrest Gump; if Zemeckis is really keen to shift to prestige projects, then this is more like the genuine article. Contact is broad in scope, and has a visual expansiveness that suggests the enormity of its thematic implications. Zemeckis has some bravura moments, including a stunning opening shot and a fiendishly clever sequence that seems to have the camera pointing directly at a mirror. Those moments (and the beautiful sequences showing the workings of the Machine) are genuinely effective and reinforce the story; they help compensate for his more blatantly grandstanding moments, such as the crane shots that pass through windows and the manipulated Bill Clinton news footage. He's got a top notch supporting cast: Tom Skerritt, James Woods, John Hurt, Angela Bassett, and even Rob Lowe. The only disappointment in his ensemble is the insufferably bland Matthew McConaughey as Foster's preacher love interest, Palmer Joss; McConaughey takes a poorly written role and runs it into the ground. Foster herself is terrific, mixing feistiness with a lingering, uncertain fragility.

Yet for all Contact's virtues - and it is one of the better American films released this year - you still can't shake that feeling that maybe Zemeckis isn't smart enough for his material. In an early sequence, the young Ellie is reciting the planets of the solar system. She gets stuck, and her insistence that her father should not help her is supposed to demonstrate both her intelligence and her strong will. Yet she's old enough that reciting the planets doesn't seem that amazing a piece of knowledge - any child prodigy worth their salt would be getting stuck on the periodic table, not the planets. It continues like this, with supposedly educated and highly intelligent people exhibiting some strange lapses. Foster's character has presumably been around university educated people most of her adult life, yet Matthew McConaughey's character impresses the pants off her (literally) by revealing that he knows what SETI stands for (I could have told her that! Will she sleep with me?). It gets worse - later on, he comments that "Occam's Razor" sounds like a horror film. In a film that strives so hard to be seen as serious and intelligent, such script details are disconcerting: they reinforce the depressing impression that Zemeckis really did think Forrest Gump was a pretty clever guy.