Up to this point in his career,

Jake Gyllenhaal

can be found, most notably, in a unique and surreal cult film (

Donnie Darko

), in sharply observed American indies (

The Good Girl

,

Lovely & Amazing

), tense Middle East conflict dramas (

Jarhead, Rendition

), a

David Fincher

-directed serial-killer thriller (

Zodiac

), an English-language remake of a Danish dogma piece (

Brothers

), and an Oscar-winning love story between two men (

Brokeback Mountain

, opposite

Heath Ledger

, of course).

So, what's this dedicated thespian doing in sixth-century armor, leaping walled citadels in a $150 million Walt Disney sword-and-sandals saga adapted from a video game?

"It's definitely a different type of movie than I've made before," says Gyllenhaal. "In the past, I looked at acting and making movies maybe a bit too seriously, and took myself a little bit too seriously. And I thought it was time to make a movie that was like the ones I loved when I was a kid."

Those would be the Indiana Jones titles, he says, The Goonies and E.T.

"And Willow," he adds, making note of the 1988 Ron Howard/George Lucas collaboration, a Middle Earth-ian fantasy made more than a decade before Peter Jackson got his hands on The Lord of the Rings.

"When I think about being a kid, I think about the wonder of these movies. And I wanted to make a movie like that. And with Prince of Persia, I thought this is a little bit of all those things mixed into one."

(Footnote for Willow aficionados: Gyllenhaal says that that film's star, Val Kilmer, served as "my inspiration for the hair in this movie" - and more. "Val really is an inspiration for this character," he insists.)

Prince of Persia: The Sands of Time opens Friday. It was shot in Morocco and at Pinewood Studios in London. Gemma Arterton, Ben Kingsley, and Alfred Molina costar, along with an army of extras, stunt doubles, horses, and CG beasts.

For Gyllenhaal, 29, getting into shape for all the running and jumping, falling and fighting required of his ancient-times action hero involved a rigorous training regimen.

"It was really, really hard," he deadpans, on the phone from Burbank, Calif., earlier in the week. "It's really hard being an actor. Getting paid to exercise. . . .

"Yeah, it was a day-in, day-out, pride-swallowing siege that you never fully know about," he continues, quoting loosely from another of his favorite films, Jerry Maguire. "There's a lot of acrobatics in the movie, and parkour, and sword fighting and martial arts. I would work with gymnasts and I would train in parkour and I'd work with the stunt guys."

Repetition, he says, was key.

"In order to do a sword fight, to really feel believable, and dangerous, doing it over and over and over again was a must. Someone said to me, which I love, 'There's nothing that 10,000 repetitions can't cure.' "

Watching old Errol Flynn swashbucklers also helped Gyllenhaal get into the groove.

"An absolute genius. He was a massive influence on this part, too."

Gyllenhaal says that he played the original, side-scrolling version of Prince of Persia when it came out on the first Mac computer. "I played it when I was a kid, and then took like a 20-year-or-so hiatus from the game," he says. "I didn't play Prince of Persia again until I started doing research for the movie, and then I played it every day, three times a day.

"Like I said, it's really hard being an actor. Getting paid to get in shape and play video games."

Gyllenhaal hails from a showbiz family. His father, Stephen (originally from Bryn Athyn), is a director; his mother, Naomi Foner, a screenwriter. His older sister, Maggie, was nominated for a supporting actress Oscar this year for her performance in Crazy Heart. Gyllenhaal's first film role was as Billy Crystal's son in the 1991 comedy City Slickers.

Since making Prince of Persia (yes, he's signed a sequel clause, "so if people respond to it, I'm back"), the actor has starred in two more typically Gyllenhaalian projects:

Source Code, "a science fiction action thriller" with Vera Farmiga, Michelle Monaghan, and Jeffrey Wright, from Duncan Jones, the director of the eerie art-house android piece, Moon.

Love and Other Drugs, a romantic comedy with Gyllenhaal as a pharmaceutical salesman who woos Anne Hathaway. Ed Zwick wrote and directed. "It's set in 1995," Gyllenhaal reports, "when Viagra was invented. . . . My character is very proficient with the ladies, so he ends up being able to sell Viagra very, very well. . . .

"Annie and I definitely got pretty intimate, because there are a lot of love scenes in the movie, a lot of sexy scenes in that movie. You have to let it all hang out, so to speak."

"Casino Jack" and other tales of corruption. Alex Gibney, the Oscar-winning director of Taxi to the Dark Side and Enron: The Smartest Guys in the Room, acknowledges that he's drawn to stories about greed and corruption, the slimy underside of the American Dream.

So what better subject than Jack Abramoff, the onetime mega-lobbyist whose questionable dealings with tribal casinos and Beltway pols landed him in federal prison?

"I'm increasingly interested in why people, or how people become corrupt, not just that they are," says Gibney, speaking from his office in New York. "Somebody like Jack, who is a zealot, who becomes corrupt because he thinks that the end justifies the means - that process is really interesting to me. And because of his worldview, too: that money and the market are a good thing, so what could be wrong with buying and selling politicians like sneakers?"

Gibney's documentary about Abramoff - Casino Jack and the United States of Money, now at the Ritz at the Bourse - plays like a spy thriller. With its mob hits and kickbacks, its bribed officials and exotic locales, it's almost too much to believe.

Except that it's all true.

"I was telling somebody the other day that it was like the voices of the Enron traders [in Enron: The Smartest Guys in the Room]. If you put them in a script, people would have said, 'Oh man, that's just too over the top, nobody behaves like that.'

"And I think the same thing goes for this story. You just think, no way, uh-uh."

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/onmovies/