‘Man Down’: As a combat vet, Shia LaBeouf never once believable

Sometimes we talk about seeing a performance so real, so believable, so authentic, it takes our breath away.

Then there’s Shia LaBeouf’s work in “Man Down.”

LaBeouf’s I’M AN ACTOR performance is so what’s-the-opposite-of-authentic, it didn’t take my breath away — it gave me optical sprains from rolling my eyeballs throughout the viewing experience.

It actually takes a talented actor to turn in a performance so off-putting. If you’re no good, you’re not interesting enough to be this far off-key. LaBeouf has demonstrated impressive talent in a number of films (“Lawless,” “Disturbia,” “A Guide to Recognizing Your Saints”), but he’s all over the place here, and never in a good way.

Even his facial hair seems to overact.

LaBeouf certainly doesn’t phone it in playing Gabriel, a combat Marine veteran who is battling PTSD, as we learn in a series of painfully dull, protracted exchanges between Gabriel and Gary Oldman’s military psychiatrist, one “Counselor Peyton.” (Oldman never gets up from behind the desk. He could have been wearing flip-flops and jean shorts throughout filming for all we know.)

Director Dito Montiel (“Empire State,” the aforementioned “Saints”) nearly gives us whiplash by bouncing back and forth along the timeline.

One minute, Gabriel is raiding a war-torn outpost where his young son Jonathan (Charlie Shotwell) is a hostage, or a kidnap victim, or something.

Cut to a scene of Gabriel, his adoring wife Natalie (Kate Mara, wasted in an underwritten role) and their son at a birthday party, where the kid gets a puppy.

Now Gabriel and his best friend Devin (Jai Courtney) are going through the hellish paces of Marine boot camp.

Now they’re in Afghanistan, at war. Now something really and truly awful happens in the heat of battle.

Now Gabriel and Devin are back home, but apparently there’s been sort of apocalyptic event in the States while they’re gone, and an unnamed force has destroyed the city they once called home.

All right, and now it’s time to return to another scene with Counselor Peyton quizzing the jumpy Gabriel, at one juncture point-blank asking Gabriel if he’s thinking of committing suicide.

The terrific character actor Clifton Collins Jr. shows up as Charles, a mysterious and scraggly street dweller who inexplicably has some vital information for Gabriel as to whereabouts of his wife and son. Gabriel and Devin scream at Charles and pummel Charles and scream some more at Charles, in an effort to find out what the hell’s going on.

Note to Gabriel and Devin: If you’re frustrated and confused, imagine how lost WE are.

Whether LeBeouf is playing the caring father and husband, the intense and laser-focused soldier, the desperate and perhaps insane veteran fighting another kind of war back home or the soldier matching wits with the Marine psychiatrist, there’s something affected about nearly every choice he makes, from the physical business to the cadence of the dialogue to the wild-eyed stares and the calculated shouting. He’s a like a basketball player dribbling behind his back and between his legs, feinting this way and that, talking trash and strutting about — to the point where we just want him to take a shot or pass the ball to someone who’s more of a team player.

Obviously co-writer/director Montiel wants to make a statement about the manner in which this country treats its returning military, and the wars raging within the minds and hearts of many a combat veteran. Gabriel is physically intact after the war, but he is a “Man Down” in so many ways.

The final sequence, when all is revealed, is overwrought, excruciatingly shrill, manipulative, and exploitative — and hardly a surprise to anyone even halfway paying attention. Like the rest of the film, it’s a cheap misfire.

★

Lionsgate Premiere presents a film directed by Dito Montiel and written by Montiel and Adam G. Simon. Rated R (for some disturbing violence, and language throughout). Running time: 90 minutes. Opens Friday at local theaters.