Sebastian Junger and the late Tim Hetherington’s 2010 documentary “Restrepo” used footage shot by the directors during ten stays with the Second Platoon of Battle Company of the 173d Airborne Division at the remote titular outpost in Afghanistan’s Korengal Valley in 2007-2008 to present as viscerally potent a cinematic portrait of the men’s combat experience as one could imagine. Now Junger has returned to the original footage to fashion what amounts to a complementary feature investigating that experience from the perspective of the men both during and after the completion of their tour. Together “Restrepo” and “Korengal” present a multifaceted view of an operation that arguably can be viewed as representing in miniature the whole of the post-9/11 American war in Afghanistan.

Where “Restrepo”—the unit’s name for their outpost, called after one of their number killed by Taliban fire—concentrated on the action in which the men were involved (hunkering down during exchanges with the enemy and venturing out to confront them or to cultivate a positive relationship with locals)—“Korengal” is more ruminative, using interviews the directors conducted with the soldiers both during and after the months they spent at Restrepo to portray how they felt about what they were doing at the time, and how they looked back on what they had done.

The picture that Junger draws is complex and compelling. The overwhelming feeling is one of camaraderie, with even the sole African-American soldier, who admits that he senses hostility toward him from his fellows, bluntly stating that he would sacrifice himself for them, and was certain they would do the same for him. There’s also a prevailing refrain about the excitement of combat, the adrenaline rush that a firefight always brings on—and that the soldiers will miss when they return stateside.

But there’s a good deal of ambivalence as well. One soldier talks almost gleefully over the charge one gets from shooting a foe and watching him fall, and others similarly note the sheer satisfaction of eliminating an enemy. But another speaks disparagingly of the idea that he was only doing what he had to, noting that he had a choice, and chose to kill; there’s a profound sadness in his recollection, an understanding that even in doing right one can be doing wrong.

The success of “Korengal” lies in its ability to convey the complicated mixture of emotions connected to the combat experience. On the one hand there’s an intense sense of belonging, along with the rush of energy and excitement that comes from engagement with the enemy—as well as the combination of boredom and fear that fills the days. On the other, there’s the mixture of pride and regret that comes afterward, especially when the tour of duty is over and one can reflect on what it meant. That’s also psychologically troubling because it brings not merely relief at being out of imminent danger, but a powerful urge to return to it. In many respects combat is like a drug it’s difficult to give up.

That’s as true for journalists who cover war as it is for the soldiers who fight it. One has to remember that in visiting for prolonged periods with the men of Restrepo, Junger and Hetherington put themselves at risk as well. Junger has covered conflict in various areas of the globe, and so did Hetherington, who died while on assignment in Libya in 2011, reporting on the civil war there. Together the films based on the footage the two shot in 2007-2008 offer a portrait of combat and its aftermath that it’s doubtful any fictional work can match in authenticity and impact.