“Casanova” has a nice package. That is to say the film sits colorfully wrapped within a framework story replete with comedy, romance and sentiment all perfectly suited to contain and conceal what is inside — nothing special. To enjoy “Casanova” is to be fooled by its tricks and wooed by its charms; but such dupery can be fun, even if it appeals to baser, far less sophisticated emotions.

As in any so-called farce, the foolishness lies mainly in the realm of contradiction. “Casanova” is an R-rated film about a notorious philanderer whose very name is synonymous with “lover” or “hunk,” but its slapstick buffoonery and merry mockery of history gives it a more “live-action Disney” feel, not unlike 1993’s “The Three Musketeers.” There is little nudity or abrasive language, while the closest thing to violence is a high school theater duel. Heath Ledger, who is incidentally most famous for his recent, exemplary portrayal of a gay cowboy in “Brokeback Mountain,” is an adequate Casanova, but seeing him leap from one end of the heterosexuality continuum to the other admittedly provides a distraction. And then there is the age-old disparity between setting and dialect. The film takes place in Venice, but instead of Italian, the characters each speak their own version of dignified English, ranging from Ledger’s Aussie mumblings to Oliver Platt’s oddly misplaced Cockney affectation.

Also lacking verisimilitude is Casanova’s rapid spurt from debauchery to romance. In early scenes he is portrayed as an unscrupulous anti-hero, an Epicurean whose delights are out of fashion in his era. Forced by authorities to choose a bride, he has no sooner done so before he finds a different woman who for some reason is perfect for him — an idealistic feminist by the name of Francesca Bruni (Sienna Miller, of handbag fame.)

Casanova soon discovers that Francesca herself is betrothed to another, and the rest of the film is a whimsical account of Casanova’s far-fetched, treacherous attempts to undo promises and win the hand of his dear beloved. Meanwhile he must also avoid the wrath of the Roman Catholic Church in the form of purpled, pot-marked priest Jeremy Irons. The result is a quagmire of conflict that must rely on vastly-contrived spectacles to reach any resolution.

There are few surprises in the film’s plot, except for the maudlin ending. Casanova expectedly tells lies to cover up previous lies, climaxing in an identity mishap of “Ms. Doubtfire” magnitude. The painfully familiar result is Francesca going through a cliched “How could you lie to me?” discourse, hardly believing it herself.

“Casanova,” at the very least, does manage to rake in a few laughs. Most of the humor comes in the form of anachronisms and double entendres, not to mention a bespattering of physical comedy. Omid Djalili as Lupo, Casanova’s manservant, is responsible for much of the pleasantry, while Oliver Platt’s naive, obese Paprizzio provides an entertaining object of ridicule. And there was a noticeable deficit of Casanova’s belligerent grandmother, who, when talking to her daughter, delivers the film’s funniest lines (“You’re a whore.” “No, I’m an actress.” “What’s the difference?”).

The film’s loftier aims are only given half-hearted intercourse. There is an attempt to make a psychological link between Casanova’s absent mother-figure and his incessant womanizing; but once presented, it is dropped throughout most of the film and never really resurfaces. Commentary on the roles of women and the politics of pleasure are better expressed in more serious dramas, or more bitingly original satires. Love, too, only gets the usual Hollywood romantic comedy treatment — oversimplification and dramatization.

There is little to say as far as acting is concerned. Heath Ledger does not single-handedly ruin the movie, nor does he make it his own. Sienna Miller, in spite of what her character might have wished her to be, is essentially a pretty face with a somewhat incredulous accent (p.s. — she’s British). The other cast members all play stock characters and are not given much of a chance to do anything creative with their roles.

“Casanova,” taken lightly, could be enjoyed. Its rare blushes of color and alacrity give it the air of good theater, a kind of commedia dell’arte that could use a bit more comedy and a supplement of art as well. And, ultimately, when faced with the pressure of performing as a legitimate drama, “Casanova” remains helplessly impotent.