Prince of Persia: The Sands of Time

If nothing else, “Prince of Persia: The Sands of Time” can claim one achievement: It’s based on a video game, yet it is not terrible. This has never happened before.

Go ahead and argue! Go ahead and list the video-game-based movies that you think were pretty decent! I will respectfully disagree. Yes, including “Silent Hill” and the first “Resident Evil.” Yes, I’ve seen them all. No, I didn’t think any of them were any good.

Not that “Prince of Persia: The Sands of Time” — or POP: TSOT, as the kids are calling it — is anything great. You probably wouldn’t even guess it was based on a game. Set at the height of the Persian Empire and starring Jake Gyllenhaal as an urchin-turned-prince who must save the throne from a usurper, the film feels more like the offspring of “Pirates of the Caribbean” and “The Mummy.” It has that jaunty, good-natured vibe, where there’s a lot of adventure and the fate of the world is supposedly at stake, but no one’s ever too serious and the characters never seem to be in great peril. It’s the kind of roller-coaster movie where an army of assassins firing arrows at the hero is fun, not dangerous.

It’s also the kind of movie where all the Persians are white and have English accents. But that probably goes without saying.

Gyllenhaal plays Dastan, an Aladdin-ish orphan who was adopted by the king (Ronald Pickup) and now, as a young man, fights alongside his foster brothers, Tus (Richard Coyle) and Garsiv (Toby Kebbell), in expanding the empire. The boys’ uncle, Nizam (Ben Kingsley), is present in an advisory capacity.

Acting on information that the holy city of Alamut is providing weapons to Persia’s enemies, the king’s armies invade and take Alamut’s princess, Tamina (Gemma Arterton), captive. She insists her city is not conspiring against the empire, and that the intelligence that told them otherwise was faulty. Search all you want! You won’t find any WMDs! (That’s not a leap. The movie is pretty broad with its political parallels, though they’re mostly goofy and don’t add up to any particular ideology.)

One small weapon that Dastan finds is a dagger of curious workmanship, which Tamina seems especially keen on retrieving. She gets her chance when someone makes an attempt on the king’s life. Dastan is framed for it and must go on the run, accompanied by Tamina, who is already his verbal sparring partner and will therefore soon become his love interest. Whether she actually believes he’s innocent is beside the point. Mostly she wants that dagger back.

The dagger is magic. It does magic things. Again I am reminded of the “Pirates of the Caribbean” franchise (which, like this, was produced by Jerry Bruckheimer), where magic and fantasy exist alongside regular swashbuckling reality. The dagger turns out to be very important, with powers that relate to the reason someone wanted the king dead, and now it’s up to Dastan and Tamina to stop the villains, save the kingdom, et cetera.

Directed by Mike Newell (“Harry Potter and the Goblet of Fire”) and written by Boaz Yakin (“Dirty Dancing: Havana Nights”), Doug Miro, and Carlo Bernard (“The Uninvited”), POP: TSOT is a smiling, if dim-witted, throwback to the Saturday-matinee kicks of yesteryear. A few sequences are genuinely exciting, and the dialogue is always snappy, occasionally funny (on purpose). It’s big but not self-consciously HUGE like a lot of blockbusters are; it feels more like an end-of-summer throwaway than a Memorial Day Weekend tentpole.

Gemma Arterton makes for a feisty princess, and Ben Kingsley and Alfred Molina (as a government-hating mercenary) give droll, high-energy performances. But Gyllenhaal, more suited to quieter roles, lacks the charisma to play the roguish adventurer he’s supposed to be here. You remember the daring heroes from “Raiders of the Lost Ark,” and even from the subpar “Mummy” movies. Dastan, not so much.

The movie runs out of steam before it’s over, and the dagger’s magic powers remove much of the life-or-death tension in the story. (Basically, whatever happens can be fixed.) But it’s modestly entertaining as far as it goes, and would be suitable for a rainy afternoon when you’ve already seen everything else at the multiplex. The movie is too cheerful and earnest to motivate any active dislike toward it, but not good enough to warrant any strong praise. It’s the reason shrugs were invented.

C+ (1 hr., 56 min.; PG-13, a lot of bloodless action violence.)