If “Captain America: The Winter Soldier” feels more like a ‘70s conspiracy thriller, that’s because it is one. Screenwriters Christopher Markus and Stephen McFeely were heavily influenced by espionage thrillers such as Sydney Pollack’s “Three Days of the Condor,” while directors Anthony and Joe Russo wanted to push the superhero movie beyond the simple action- and nemesis-driven plots we typically see. How unusual is it for a superhero NOT to appear in just about every scene of a superhero movie? But of course it isn’t unusual for that to happen in more complex thrillers.

“The Winter Soldier” takes its title from a Soviet agent that Captain America (Chris Evans) goes up against, but that assassin (Sebastian Stan) is only one piece of the puzzle in a complex plot that twists and turns like Steve Rogers own souped-up DNA.

The action picks up two years after “The Avengers” and the “Battle of New York.” Rogers, revived decades after he was frozen in suspended animation, has to adjust to a life in which everything is radically different. That alone provides plenty of interest and a psychological substrate, but he’s also working for S.H.I.E.L.D., a spy agency run by director Nick Fury (Samuel L. Jackson). On a mission to free hostages from a group of mercenaries, he discovers that the agent accompanying him (Scarlett Johansson as Natasha Romanoff) has a different assignment—to hack into the ship’s computers and bring back the data.

Soon, Rogers becomes suspicious of everyone, especially after a group of assassins led by the Winter Soldier try to take him out. Both the action and the intrigue accelerate, all because of that flash drive—though that, too, is far from the whole story. There are moles and double agents and the preserved brain of a supervillain named Arnim Zola and an organization named Hydra that springs up right inside S.H.I.E.L.D. And just when you thought you’d seen the last of the acronyms, along comes S.T.R.I.K.E. and Insight Hellicarriers that function like precision-targeted drones.

The stakes are high, too: lives hang in the balance and the world is on the brink of a new age of “miracles” . . . and warfare. It’s also the beginning of an age where everything isn’t the moral equivalent of black and white. There are plenty of gray areas, and Fury is probably the poster child for the new end-justifies-the-means mentality.

The filmmakers cast Robert Redford as a senior S.H.I.E.L.D. operative, partly as a nod to “Three Days of the Condor,” in which Redford starred with Faye Dunaway, Cliff Robertson and Max von Sydow. But Redford is as believable as the rest, and it’s good to see him in a thriller again.

Taking the thriller approach works well, in fact, because it automatically solves a problem that has plagued every director of every superhero movie:  how do you get the tone right? How serious, or how comic-book do you go? Well, the espionage thriller comes with its own conventions, and it makes for a nice fit . . . at least with this particular superhero.

“The Winter Soldier” comes to a 50GB Blu-ray via a sparkling AVC/MPEG-4 transfer. Colors are vibrant, detail is strong even in numerous low-light and shadow sequences, and edge delineation gives even the 2D version a 3D look at times. If there were any artifacts or imperfections, I didn’t see them. The film is presented in 2.40:1 aspect ratio.

The audio is just as apparently flawless—unless there are people in your family who don’t like the effects portion of a film to be so much louder than the dialogue. The featured soundtrack is a booming English DTS-HD MA 7.1, and it’s about as immersive as it gets. But you do find yourself turning the volume down during strong action sequences and up again when the dialogue becomes incomprehensible.

A brief tour of the bonus features has to start with the full-length commentary from the Russo brothers, who considered the film as a challenge and a problem to be solved. As they walk you through their solutions you develop an even greater appreciation for “The Winter Soldier.” Many commentary tracks are by-the-numbers low-energy affairs, but maybe that’s because they figure no one cares to listen . . . not that they don’t have much of significance to say. But when you cover new ground there’s always something to say, and this track is worth your time.

Aside from that, though, there isn’t much. A 10-minute making feature gives you the usual cast and crew talking about the film and the evolution of Captain America, combined with some behind-the-scenes shots of the filming. Then there’s a shorter (2 min.) mini-feature on Anthony Mackie as Falcon, a 3-minute look at Steve Rogers’ notebook, a gag reel of equal length, and four minutes of deleted/extended scenes with optional commentary from the directors.

Bottom line:
“Captain America” was a solid superhero film, but “The Winter Soldier,” with its greater complexity and sustained tension, is better still.