The words "alien" and "predator" are never used in the film "Alien vs. Predator," and in fact both of the headlining monsters could be described with either term. The only way you know which is the "alien" and which is the "predator" is that you've seen the movies that bore those titles and are thus familiar with each creature's modus operandi: The "alien" is the phlegmy, reptilian thing that used to terrorize Sigourney Weaver in outer space, while the "predator" is a dreadlocked humanoid that used to terrorize Arnold Schwarzenegger or Danny Glover on Earth.

Apparently, they also terrorize each other -- though we do not see this first-hand until 53 minutes into the film -- and are unconcerned about incurring collateral damage in the form of any humans who happen to be nearby. You may be assured that in "Alien vs. Predator," many humans are dispatched, in approximately the same order they usually go in slasher films (nameless characters first, then mean characters, then people we like, and so forth), which is essentially what this is.

The setting is an especially remote part of Antarctica, where ailing billionaire Charles Weyland (Lance Henriksen) has brought a crack team of experts, guides and scientists to investigate something his satellites spotted 2,000 feet below the ice: a pyramid. Alexa Woods (Sanaa Lathan), who was ice-climbing in Nepal when she got the call, says it's too dangerous for them to go exploring without proper training, but Weyland urges them forward anyway, for fear some other satellite-owning entity will be tipped off and get there first.

Like the crews in movies such as "Armageddon," "The Core" and Disney's "Atlantis," this crew is an eclectic mix of different personality types and accents, including a Scottish family man (Ewen Bremner), a hunky Italian archeologist (Sebastian de Rosa) and a gruff American oil driller (Carsten Norgaard). These are not "characters," exactly, but types, and I'm puzzled why the film spends so much time with them before showing us the real action. I always marvel at such wrong-headedness in these movies: Haven't the filmmakers seen movies like this before and wished, as their audience does now, that they would just get on with it?

The director and writer is Paul W.S. Anderson, maker of such overwrought, over-violent fare as "Mortal Kombat," "Soldier" and "Resident Evil." His fondness for the "Alien" franchise and the two "Predator" films seems to stretch only as far as it suits him, as he ignores their respective mythologies whenever he pleases and writes new history for them both. Viewers with only a passing knowledge of either series, though, may find the tying-together of the monsters' stories to be perfectly reasonable.

Anderson was apparently hampered by 20th Century Fox's request that the film be PG-13 (despite all of the "Alien" and "Predator" films having been R), meaning he couldn't be as graphic as he wanted to be, and as many of the fans wanted him to be. Perhaps he doesn't know how to make a PG-13 film (it's only his second one, out of the six he's done). In several instances, a scenario is set up but not finished, or an outcome is implied but not directly resolved, simply because Anderson couldn't show what he wanted. It's sloppy.

All of which is sort of beside the point, because what you REALLY want to know is, are the action scenes fun? And they are, mostly. Realizing that only one species can win, the surviving humans pick the favored monster and form an alliance with it that is surreally funny, probably more so than the film intended. That leads to a last act that is, if not clever or original, at least peppy. Most of the film is good enough that way: dumb, but not boring.

Grade: C

Rated PG-13, a little profanity (including one F-word), a lot of sci-fi violence and some blood

1 hr., 40 min.