“Lone Survivor” opens Friday at Point, Eastgate, Star Cinema and Sundnce. R, 2:01, three stars out of four.

Peter Berg shoots the opening moments of “Lone Survivor” as if he was making a recruiting commercial for the Navy SEALS. Stirring music plays as we see real-life footage of Navy SEALS going through grueling basic training, a hardy few making it to the end.

Maybe it’s a good thing, because after seeing the rest of the grueling war film, I can’t imagine anyone in their right mind showing up at the recruiting office. “Lone Survivor,” based on the memoir by Navy SEAL Marcus Luttrell is a punishingly exacting recreation of a tragic 2005 incident in the mountains of Afghanistan. I hope it’s not a spoiler to confirm that the title of the movie is itself a spoiler.

Mark Wahlberg plays Luttrell, one of a team of four NAVY Seals (along with Ben Foster, Emile Hirsch and Taylor Kitsch) dropped into the remote mountains as part of a larger operation to capture a vicious Taliban leader. They’re supposed to hide in the mountains, watch the Taliban compound and provide intel for the strike team that will come later. One thing they discover is that the compound is much more heavily defended than the SEALS anticipated, to the tune of a couple of hundred soldiers.

The early scenes of “Lone Survivor” vibrate with tension because Berg is so committed to realism, showing the team patiently getting into position, watchful. But things go to hell when they’re spotted by a trio of goatherders.

Now the SEALS have a choice; they can let the possibly innocent goatherders go, and risk them revealing their position to the Taliban. Or they can detain or even quietly kill them to preserve the mission. Interestingly, this is apparently the one scene in the movie that Berg fudges with the facts on. In the film, the debate between the four soldiers is protracted, and Berg clearly stacks the deck in favor of killing the goatherders. (One teenage Afghan looks clearly untrustworthy, his eyes full of hate at the Americans.) In real life, apparently, there was no debate. They let them go, because that’s what protocol dictated.

A few hours later, the Taliban soldiers come storming up the hill. And all hell breaks loose.

“Lone Survivor” will remind many of Ridley Scott’s “Black Hawk Down” in the sense that it is basically one long, brutal battle scene, played for maximum realism, with the heroes facing a vastly superior and seemingly inexhaustible force. At first, the superbly trained SEALS seem to be able to hold them off — Berg keeps the camera close, registering every play of emotion on their grim faces as they dig in. But they gradually start getting worn down, the line gets broken, and the soldiers end up retreating under a hail of machine-gun and RPG fire, running, jumping and often falling down the side of the mountain.

This is brutally efficient filmmaking — Berg seems to never pass up the chance to show us a bullet wound or a broken bone, and many of both accumulate as the SEALS try desperately to stay alive. Berg clearly lionizes the military, and one could read the hard realities of “Lone Survivor” as a bit of an apology for the shiny video-game nonsense of Berg’s last movie, “Battleship.” The performances are all effectively low-key, especially Foster as the thoughtful Matthew Axelson and Wahlberg as Luttrell. How he stays alive I won’t reveal, but the film puts him through a wringer both physically and emotionally.

Berg said his mission in making “Lone Survivor” was simply to tell the story of Luttrell and the other SEALS, to make the audience feel what they went through as much as possible. Mission accomplished. But I am still troubled by that one fictionalized scene where they debate the fate of their captives. In real life, the SEALs were even more heroes because they flatly refused to compromise their principles. Berg, a filmmaker who deals in good guys and bad guys, can’t see that.

He sees their bravery in combat. But they earned our respect and admiration before the first shot was even fired.