"Fun" and "bewildering" are words you rarely hear used together to describe a movie.

Yet both certainly apply to "The Matrix," a science-fiction/action film so alternately thrilling and frustrating that it almost defies description.

Try to imagine — if you can — a wild and woolly combination of "20,000 Leagues Under the Sea," spaghetti westerns, martial-arts action films, "Virus," "Men in Black" and "The Terminator," among others. The result might be something close to what this film is like — but the results would still fall short in terms of entertainment value.

"The Matrix" is far from perfect. In fact, it's ambitious to a fault and the plot is so ridiculously convoluted that some audiences will leave the theaters scratching their heads. If that's not enough, the whole thing is at least 20 minutes too long.

But there also hasn't been a science-fiction film this entertaining for a long time. And it also makes another credible case for Keanu Reeves as an action star.

Reeves stars as Thomas Anderson, a computer programmer who moonlights as a hacker (under the nickname Neo).

That side career has left him a wanted man, and he is pursued by Trinity (Carrie-Anne Moss), an operative working for underworld figure Morpheus (Laurence Fishburne). Also in pursuit is a sinister trio of men in black, led by the mysterious Agent Smith (Hugo Weaving).

While Morpheus is trying to recruit Neo to join his band of freedom fighters, Agent Smith wants Neo to spy on Morpheus. It isn't an easy choice, but Neo opts for the former.

And with Morpheus' help, he discovers a mind-boggling secret: His "reality" is actually a computer-generated artificial universe created by a mechanical intelligence that is now ruling the Earth. Even more startling is the fact that Morpheus believes Neo may have the power to free mankind.

If that's not too clear, hold on — the plotting gets even more more confusing.

But the filmmaking Wachowski brothers ("Bound") aren't really as concerned with exposition as they are with creating startling images and quick-moving action sequences.

Helping in that department is a series of superb martial-arts fight scenes, choreographed by Yuen Wo Ping, frequent collaborator for former Hong Kong star Jet Li.

Also, credit Reeves and his co-stars, who display great physical skills, as well as surprising acting prowess (especially the scene-stealing Weaving).

"The Matrix" is rated R for violent gunplay and martial-arts fighting, profanity, gore, use of vulgar sexual slang and vulgar gestures, drug use, a scene of torture and fleeting male nudity.