In theaters

CASANOVA, directed by Lasse Hallstrom, written by Jeffrey Hatcher and Kimberly Simi, 108 minutes, rated R.

In Lasse Hallstrom’s “Casanova,” Heath Ledger comes off the success of “Brokeback Mountain” with a performance that just doesn’t get the job done.

Here, as the great 18th-century lover, Giovanni Giacomo Casanova, Ledger initially is all pony behind the ponytail, trotting through his alleged 10,000 sexual conquests – from the corseted ladies of high society to the looser trade found on the streets to a few scandalously, heretically passionate nuns – as if he were perfectly game for the sport, which by all appearances he is.

Watching him bed hop with so many women is enough to make you want to send Jake Gyllenhaal a note of condolence, urging him to remember the good times at Brokeback – the fireside canoodling – and that we’re just as surprised as he is by Ledger’s somewhat telling and immediate follow-up to “Brokeback.”

But then you finish “Casanova” and you realize that Ledger should be the one receiving the condolences. When you’re being seriously considered for an Academy Award, as Ledger is for “Brokeback,” this is not the sort of movie you want lingering in voters’ minds, particularly since it has tanked at the box office, which is a far greater sin in Hollywood than anything those aforementioned nuns have done.

About the nuns. The Catholic Church wants Casanova hanged for seducing them, but the Doge (Tim McInnerny) intervenes, proclaiming that if Casanova marries the presumably “pure” Victoria (Natalie Cormer) and puts a stop to his philandering ways, he might be spared.

All of that sounds well and good, but catching Casanova’s eye is Francesca, a tense piece of work with a secret life who is played by Sienna Miller with so much hard-mettled moxie, it’s tough to like her.

Worse for Miller, who perhaps came to the part overly prepared given her own real-life woes with the philandering Jude Law, she has almost no presence here. Just when she should command the screen most, she tends to disappear, which begs the question what it is that Casanova sees in her. A cross-dresser? Perhaps, since she is one.

Helping the proceedings somewhat is Oliver Platt as the overstuffed, overfed creature, Papprizzio, who has made a fortune shucking lard; Hallstrom’s own wife, Lena Olin, as Francesca’s fantastically bewigged mother; and Jeremy Irons as the inquisitor Bishop Pucci, who gives a performance that makes everyone in “The Producers” seem tame by comparison.

In the end, what sinks “Casanova” is that history knows he was a far more interesting man than the horny dullard presented here. From Jeffrey Hatcher and Kimberly Simi’s script, this slight, silly costume comedy gives the illusion of frivolity and movement, but in spite of its teaming onslaught of subplots, it’s oddly static and uninvolving. The film is played as farce, which robs it of the serious emotion it ultimately courts. It’s a film in which the sight of a lovely hot-air balloon floating high above Venice amid a sea of exploding fireworks is as dangerous as the story gets.

Grade: C-

On video and DVD

LORD OF WAR, written and directed by Andrew Niccol, 122 minutes, rated PG-13.

Andrew Niccol’s “Lord of War” is about international gunrunning, with one Yuri Orlov (Nicolas Cage), a Ukrainian-born, Brooklyn-bred kingpin raised Jewish by parents who wanted to capitalize on the fruits of the locals, helping to arm the third world.

Over the course of two decades, we follow Yuri’s sorry life, watching him gradually face the manipulative, unlikable core of who he is in the wake of the mass death he unleashes globally. Not that his connection to those deaths trouble him much. Yuri is in this for Yuri.

The movie, which Niccol based on his own script, begins with a spectacular scene of computer animation. In it, Niccol follows a single bullet’s harried path from a manufacturing plant in Russia to the jungles of Africa to the throes of a bloody street war and finally to the center of one young boy’s forehead.

Cut to Yuri, who supplied those guns and who now is standing amid a wasteland of death and smoking wreckage. “There is one firearm for every 12 people on the planet,” he says to the screen. “The challenge is to figure out how to arm the other 11.”

Yuri isn’t a good man, he’s the kind of guy who likes to brag that he sold Israeli-made Uzis to Muslims, so what ensues is a story that follows his efforts to get people the guns they want. Helping him is his cocaine-addicted brother, Vitaly (Jared Leto), who is useless. Hindering him is an Interpol agent played by Ethan Hawke, who is naive. Yuri’s beautiful wife, Ava Fontaine (Bridget Moynaham), is pure window dressing. She’s a former model who is neither here nor there, just like their young son, who was obviously brought in to punctuate just how far Yuri has fallen from what matters.

Or at least what should matter. The problem with “Lord” is that Yuri is so amoral, nothing really matters to him but money, power, the rush of selling guns.

Since it’s impossible to like him, that feeling extends to the movie he inhabits. Since his behavior becomes so repetitive and predictable, the film follows suit – long stretches are redundant.

“Lord of War” has flashes of good writing and acting, but for those who pay attention to the news, its story won’t seem particularly new. Add it up, and what you have is a movie that takes its own bullet in the gut.

Grade: C

Visit www.weekinrewind.com, the archive of Bangor Daily News film critic Christopher Smith’s reviews, which appear Mondays in Discovering, Fridays in Happening, and Weekends in Television. He may be reached at Christopher@weekinrewind.com.