The Vatican newspaper and radio station criticised James Cameron's 3-D blockbuster Avatar for flirting with the idea that worship of nature can replace religion - a notion the pope warned against.
They call the film a simplistic and sappy tale, despite its awe-inspiring special effects.
"Not much behind the images" was how the Vatican newspaper, L'Osservatore Romano, summed it up in a headline.
As the second highest-grossing movie ever, Avatar is challenging the record set by Cameron's previous movie Titanic.
Generally it has been critically acclaimed and is touted as a leading Oscar contender.
Bolivia's first indigenous president, Evo Morales, praised Avatar for what he calls its message of saving the environment from exploitation.
But the movie also has drawn a number of critical voices. Some American conservative bloggers decried its anti-militaristic message; a small group of people have said the movie contains racist themes.
To Vatican critics, the alien extravaganza is just "bland".
Cameron "tells the story without going deep into it, and ends up falling into sappiness," said L'Osservatore Romano.
Vatican Radio called it "rather harmless" but said it was no heir to sci-fi masterpieces of the past.
Most significantly, much of the Vatican criticism was directed at the movie's central theme of man vs. nature.
L'Osservatore said the film "gets bogged down by a spiritualism linked to the worship of nature".
Similarly, Vatican Radio said it "cleverly winks at all those pseudo-doctrines that turn ecology into the religion of the millennium.
"Nature is no longer a creation to defend, but a divinity to worship," the radio said.
Vatican spokesman Fr Federico Lombardi said that while the movie reviews are just that - film criticism, not theological pronouncements - they do reflect Pope Benedict XVI's views on the dangers of turning nature into a "new divinity".
Benedict has often spoken about the need to protect the environment, earning the nickname of "green pope." But he also has balanced that call with a warning against turning environmentalism into neo-paganism.