When I saw “Patriots Day” last month, I was marginally impressed by its level of class and authenticity. Then I tuned into to see HBO’s “Marathon.” That was game, set and match as to which is the superior postmortem on the horrors of April 15, 2013. And the difference is that the latter is emotionally stirring and deeply human, and the other a cold, calculated re-enactment bordering on exploitation.

Yes, I know the city of Boston owes a humongous debt to its first responders and investigators, but “Patriots Day” pays short shrift to the real heroes — the victims. Do we really need a star-studded redo of the bombings, the seemingly endless shots of the FBI poring over surveillance tapes, a stomach-turning depiction of MIT cop Sean Collier being fired upon point blank multiple times and a Hollywoodized version of the infamous Watertown shootout between law enforcement and the two scumbags I shall not name? Director Peter Berg and muse Mark Wahlberg seem to think so. But let us not forget that both are driven by a profit motive that dictates the more tickets you sell, the more money you make. So we get a movie that — although its heart is in the right place — resembles a summer blockbuster, complete with Wahlberg playing the snippy, indestructible cop who will always save the day. In fact, his character, Boston Police detective Tommy Saunders, is a manufactured composite. But having Tommy play a hand in every major development goes completely against the film’s intent to depict the investigation as a total team effort.

Then there’s the bane of every movie set in Boston — the bad accents. Even Wahlberg’s sounds off a bit, and he’s from Dorchester. As for John Goodman as Boston Police Commissioner Ed Davis, James Colby as police Superintendent Billy Evans and Vincent Curatola (Johnny Sack from “The Sopranos”) as Mayor Menino, it’s grating, taking you right out of the movie. J.K. Simmons as Watertown Police Sergeant Jeffrey Pugliese fares slightly better, as does Kevin Bacon (doing his third Hub-set movie after “Mystic River” and “Black Mass”) as the FBI’s chief investigator Richard DesLauriers.

But acting is not the film’s most jarring flaw. It’s the script. Amazingly, it took five people, including Berg, to assemble a screenplay for a movie that pretty much copies everything you saw live on CNN during the week of April 15-19, 2013. Except for Wahlberg’s omnipresent cop, the movie offers zero character development. It’s almost entirely expository dialogue and the usual shouting matches when politicians, the FBI and local police clash over how to best handle the investigation, mainly when to release the pictures of “White Hat” (Alex Wolff) and “Black Hat” (Themo Melikidze) to the press.

Enough of the bad. What’s good about “Patriot’s Day?” Two things, really. The first is Jimmy O. Yang as Dun Meng, the man the terrorists carjacked in Cambridge after they murdered Collier, and the second is Melissa Benoist as Black Hat’s widow, Katherine Russell, who we watch undergo intense interrogation by Khandi Alexander’s counterterrorism agent. It’s no coincidence why these are the film’s highlights, and that’s because they are the only two facets of that tragic week we were never privy to on TV. And Berg shows how fine a director he can be in how he stages both scenes for maximum tension and unease. You’re riveted.

I only wish he’d done the same with the victims, or at least the precious few we actually meet. He includes newlyweds Jessica Kensky (Rachel Brosnahan) and Patrick Downes (Christopher O’Shea), who were taken to separate hospitals after losing limbs in the explosions, neither of them knowing if the other was alive until days later. Typical of Berg’s just-the-facts approach, he never tells us the wrenching hurdles awaiting the couple in the months ahead. “Marathon” did, and in many ways you wish “Patriots Day” did the same. That’s the real story of the bombing: The long, arduous recovery of the injured, the maimed and the families of the dead. Also the city. All we see in terms of the Hub’s healing process again are re-enactments, mainly the ovation law enforcement received when they pulled out of Watertown after nabbing White Hat, and David Ortiz dropping the F-bomb at Fenway during a ceremony honoring the first-responders.

It’s just not Berg’s thing, I guess. His approach was equally mechanical in his re-enactments of the oil-rig explosion in “Deepwater Horizon,” and in the band of U.S. soldiers under heavy fire in “Lone Survivor,” both of which also starred Wahlberg. What Berg does have is a strong eye for visuals, and the one scene in “Patriots Day” I’ll never forget is the brief cutaway to a state trooper standing guard over the corpse of 8-year-old Martin Richard, whose sheet-covered body remained on a Boylston Street sidewalk for hours after the blast. I get teary just thinking about it. And that’s the level of emotion that the picture required but seldom delivers.

What we get plays like one of those docudramas such as “Killing Kennedy” and “Killing Reagan” that National Geographic spits out based on books by Bill O’Reilly. Throughout, that week of terror is chronicled by Berg with digital readouts telling us the time and day, like 5 hours before marathon and 5 hours after blast. The other constant is Wahlberg, whose hard-drinking homicide detective we learn is on probation with his superiors. We first meet him in the predawn of April 15, when he’s the lead cop on a drug bust, injuring his knee kicking down a door to a crack house. Then it’s home for a short rest before having to pull mandatory crowd-control duty at the marathon’s finish line.

In between those assignments, we see Tommy with his doting wife, Carol (Michelle Monaghan), scenes that are almost a carbon copy of Wahlberg with Kate Hudson before heading off into disaster in “Deepwater Horizon.” Well, if it worked once … From then on, Tommy is our eyes and ears, as he’s first on the scene after the explosion, then collecting evidence, reassembling it on a grid inside the Black Falcon terminal and then helping search for clues in the hours of surveillance videos confiscated from businesses along Boylston Street. And when it comes time to pursue the suspects, he’s Tommy on the spot at the Watertown shootout and the flushing of White Hat out of the boat behind 67 Franklin. In other words, the focus is always on him instead of the people who really matter. It’s particularly frustrating because, frankly, Tommy’s know-it-all act quickly grows tiresome. The only other semblance of character depth is seeing Simmons’ character stopping by a Dunkies to get coffee and doughnuts.

Still, the film looks great, particularly the fly-over shots of Back Bay and the level of realism in the aftermath of the explosions. It’s definitely not for the squeamish. You always feel like you smack in the middle of the investigation. But that’s about all you feel until pictures of the real victims pop up at the end. It’s then that you dissolve into tears. But by then, you may have already dropped out of the race.

“Patriots Day”

Cast includes Mark Wahlberg, Kevin Bacon, J.K. Simmons, John Goodman, Jimmy O. Yang and Michelle Monahan.

(R for violence, realistically graphic injury images, language throughout and some drug use.)

Grade: B-