Plenty of other pictures had exploited the idea of a trapped group of people fending off invaders — “Straw Dogs,” “Night of the Living Dead” and a handful of westerns, for example — but few had broken it down to such a primal level.

Nearly three decades later, the project has been given a glossy face-lift. Instead of a fanatical street gang laying siege to cops at a decommissioned Los Angeles precinct in retaliation for the deaths of some members, the setting has been moved to snowy Detroit. The cops are now guarding a drug lord (Laurence Fishburne), and this time it’s a S.W.A.T.-equipped team of police higher-ups who are doing the assailing — former partners of the criminal who want to prevent him from testifying against them.

Hip-hop video director Jean-François Richet and writer James DeMonaco (“The Negotiator”) attempt to make a number of improvements to the rather simplistic plot. The original was weak in terms of characterization, so more colorful roles are crafted to showcase an array of talented actors.

Ethan Hawke stars as Sgt. Jake Roenick, an undercover officer who was wounded during a messy drug-bust shoot-out and now chooses to “hide behind a desk” and bottles of painkillers as a way of burying the guilt.

On New Year’s Eve, Roenick and the last remnants of the soon-to-be-defunct precinct must baby-sit a batch of prisoners that have been rerouted to the locale because of a worsening blizzard. Included is the infamous Marion Bishop (Fishburne), a paranoid junkie (John Lequizamo) and a few other petty crooks. Also stranded at the station is a veteran cop on the verge of retirement (Brian Dennehy), a sex-starved secretary (Drea de Matteo) and a police psychologist (Maria Bello) sent to evaluate Roenick.

Once the bad guys outside start strapping on the body armor and night vision gear, “Assault on Precinct 13” is pretty much what its name implies. The movie strives to make the motley crew take a proactive stand to escape their predicament, rather than just react to what the enemy throws at them. And the internal conflict really escalates once Roenick is forced to arm the twitchy criminals in his care using the random assortment of weapons stored in the police evidence locker.

However, as the filmmakers try to raise the tenability of the project, they inevitably lose much of the B-movie charm.

Despite a fine frenetic prologue and the engrossing centerpiece assault, the third act comes apart by trying to get too complicated … and it does so rather painfully.

As soon as the principal players are removed from the precinct setting, the film becomes like any other good cop vs. bad cop action vehicle. The tension seeps out of the story, which turns rife with predictable confrontations and conclusions.

Worse, a plot twist is revealed that makes no sense. If a “mole” was introduced to infiltrate the survivors, why wouldn’t this person simply have killed Fishburne’s gangster — there are scads of opportunities — thus ending the conflict? Answer: Because then there would be no ridiculous trick ending.

Let it also be noted this is one ultra-violent production. There are numerous images of gratuitous gunshot wounds, amplified by director Richet’s almost fetishistic fixation on close-ups of actors with a single bullet hole in the head.

Sure, the original flick had some unforgettable scenes of abrupt violence, including one involving an ice-cream truck that is always referenced by fans of Carpenter’s work. But it was the unpredictability of these moments that resonated, not the gory mechanics of squibs exploding and blood packets oozing.