All these soldiers and scientists and heroes and anti-heroes in “The Predator” act as if they’ve never seen any movies about aliens or fantastic beasts or human-engineered dinos.

When are they going to learn steel restraints and knockout drugs are only going to aggravate the thing when it wakes up?

“He’s heavily sedated,” says a scientist of a captured predator who is strapped down on a table but otherwise un-caged in the middle of a busy lab, while dozens of researchers go about their business, as if they were sharing space with a hibernating hamster.

Idiot.

Also, shouting obscenities and insults at an 11-foot killing machine as it tears apart your colleagues probably isn’t going to get under the guy’s skin, so to speak.

And if you run out of ammunition, don’t THROW your weapon at the beast. It’s just going to bounce off him like a toy.

We see a number of sometimes irritatingly dated action-movie clichés in Shane Black’s slick and gory and well-made but surprisingly unimaginative sequel to the “Predator” franchise, which makes references to the events of the original from 1987 as well as the 1990 sequel, and even manages to drop in a forced callback to the most famous line from the first movie.

It also leaves the door wide open to at least one more chapter in the franchise, but I can’t say this effort set off fireworks of anticipation for another sequel.

The screenplay by director Black and his co-writer, Fred Dekker — that’s right, they’re Black and Dekker — feels like it was dusted off from the late 1980s, with politically incorrect characters and jokes; a wisecracking band of rogue soldiers with severe mental and emotional problems, and a father who takes out an opponent by shooting him in the eye with a tranquilizer gun, and doesn’t even pause to see if his adolescent son has been traumatized by witnessing the incident up close.

Not that we expect sensitivity and sugarcoated dialogue in a “Predator” movie. I’d much rather see a hard-R, f-bomb dropping, squishy-kill-filled “Predator” than some watered-down edition.

The problem is, despite the efforts of the talented cast, the supposedly lovable former soldiers aren’t all that lovable, the primary human villain is a cocky fool with cloudy motives — and the predators don’t seem all that intimidating compared to a lot of the Earth-loathing alien invaders we see at the movies these days.

Oh, and when the biggest, baddest predator accesses a translating device and speaks to the humans in English, a moment that should be chilling is inadvertently campy, as if we’re suddenly playing an arcade game from 30 years ago.

Boyd Holbrook has the kind of role Michael Biehn would have played a generation ago: blandly handsome professional sharpshooter Quinn McKenna, who sees his team wiped out in a Mexican jungle by a predator whose ship has just crash-landed. McKenna manages to escape with the helmet and the arm gauntlet of a predator — and he mails it to a post office box near his home so he’ll have evidence to back up his story while the military tries to prove he’s suffering from PTSD and is delusional.

Only one problem: McKenna forgot to keep the payments on the P.O. box (I’m not kidding), so the package lands at the doorstep of his estranged wife Emily (Yvonne Strahovski) and his sixth-grade son Rory (Jacob Tremblay), a savant who’s “on the spectrum” and has serious math and science skills.

Rory quickly figures out how to use the helmet and the mysterious McGuffin of a device embedded in the wrist armor, so now the race is on between Rory’s dad and his team, the predators and the ruthless government mercenaries led by Sterling K. Brown’s sadistic Traeger to see who can get to Rory first.

McKenna’s team of “loonies” — former soldiers who were on their way to an institution when all hell broke loose — includes Trevante Rhodes’ Nebraska Williams, who once shot himself in the head; Keegan-Michael Key’s Coyle, who cackles wildly and tells “Yo mama” jokes; Thomas Jane’s Baxley, whose Tourette’s gives the filmmakers an excuse for Baxley to say something vile and crude to … Olivia Munn’s Casey, a research scientist who suddenly becomes an action hero early on, capable of firing automatic weapons and taking down heavily armed guards and leaping from high perches onto moving vehicles.

Munn’s best work comes when she uses her wits to disarm the dopey guys. Sterling K. Brown goes all out, but is saddled playing a character who keeps making stupid decisions even as he chomps on his gum and guffaws at his “inferiors.”

The best performance in the film comes from Jacob Tremblay, who was so good in “Room” and “Wonder,” and once again is playing a boy dealing with enormous challenges. Tremblay’s work is so strong, so subtle, so natural, it’s as if he’s in another, much better movie.

‘The Predator’

Twentieth Century Fox presents a film directed by Shane Black and written by Black and Fred Dekker. Rated R (for strong bloody violence, language throughout, and crude sexual references). Running time: 101 minutes. Opens Friday at local theaters.