Before, it was “In space, no one can hear you scream.”

But then those pesky Predators brought the battle to Earth.

And now the hapless humans find themselves with ringside seats at the brawl of the century: Alien vs. Predator.

Although the “Alien” and “Predator” movie franchises have charted separate courses in the past, their fans have been craving a showdown for quite some time. Comic book and video game spin-offs brought the two species together to much fanfare, and the movie “Predator II” suggested the same might happen on the silver screen when it placed an Alien skull among the hunting trophies on the Predators’ space ship.

Now, writer, director Paul W.S. Anderson has brought the idea to fruition in “Alien vs. Predator” (AvP).

Far better than 1997’s “Alien: Resurrection,” “AvP” puzzles as much as it impresses. It pales in comparison to its other forebears, namely because it lacks the deft handling of suspense and surprise sequences that its predecessors mastered.

Other notable omissions include any resemblance of a respectable cast (no Arnold, no Carl Weathers, and worst of all, no Sigourney Weaver), a memorable soundtrack like Jerry Goldsmith’s and James Horner’s scores (“Alien,” “Aliens”) and a complete lack of common sense. As the characters traipse around the Antarctic ice shelf in light clothing, one wonders if the writers had ever heard of frost bite.

Yet the movie does very well at what the title suggests – pitting the Alien against the Predator, and the fight sequences do impress.

The translucent story line begins with a team of explorers traveling to Antarctica to investigate unusual heating patterns below the ice detected by satellite images. While canvassing the icy topography, the team discovers an ancient subterranean pyramid that, much to their chagrin, serves merely as a shape-shifting arena for Predators to come to Earth and hunt their Alien prey.

Certain “sacrificial chambers” incubate Alien eggs that have been produced by the Predators’ captive Alien queen, and once the humans discover the eggs, Alien facehuggers attack and the hunt begins.

Up until this point, the movie makes little sense and offers little for the avid fan or the casual moviegoer. Once the Predator meets the Alien, though, with the humans stuck in the middle, the gloves come off.

Here’s where Anderson really shines as the director – he’s really a fan himself.

His team took considerable liberty with creating modern versions of the creatures and the Predators’ dazzling weapons. Something new, something old, it all works well. And while details may have been overlooked in areas of realism, every nuance of the alien species’ spectacular anatomy receives the utmost attention, right down to scars attained during battle.

Once the action takes off, it never idles for a moment, and the movie seems to end much too soon, save for a spectacular surprise ending that leaves the audience wanting more.

Fans of “Alien” and “Predator” should find a lot to like in this offering. It’s not a sequel, it’s not a prequel; it’s more of a free-for-all.

For everyone else, “AvP” will please (at best) but not enthrall. In theatres, no one will hear you scream.