To tell the truth, we could have done a lot worse with the updated big-screen version of "Lost in Space" - a whole lot worse.

In fact, when compared to other recent movies made from existing television series (anyone want to see either "A Very Brady Sequel" or "Mr. Magoo" again?), this futuristic adventure almost seems like a masterpiece. At least it's exciting for much of its breathlessly paced first hour.Unfortunately, after that the film loses its way (excuse the pun), with some pretty superficial character developments and a time-travel plot so convoluted that many audiences will leave theaters wondering what it was about.

Still, there are a couple of good messages buried under all the special effects, pertaining to environmental concerns and the importance of family. But there are also some scary moments that might frighten young viewers.

The film wisely jumps right into the story, as the Robinson family - John, the father (William Hurt); Maureen, the mother (Mimi Rogers); and children Judy (Heather Graham), Penny (Lacey Chabert) and Will (Jack Johnson) - prepares to travel into space so they can colonize Alpha Prime, the only other habitable planet in the galaxy.

But their ship, the Jupiter 2, also has a stowaway - the evil Dr. Zachary Smith (Gary Oldman), who was trapped while trying to reprogram the Robinsons' robotic servant (again voiced by Dick Tufeld), to turn it into an assassin.

Family members and intrepid pilot Don West (Matt LeBlanc) finally succeed in stopping the rampaging robot, but in the struggle the spacecraft is damaged and is thrown way off course - and possibly out of their own time frame.

Despite their differences, the family is forced to come together and become unwilling allies with Dr. Smith when they encounter a "ghost" ship that contains deadly and voracious space "spiders."

Screenwriter Akiva Goldsman ("Batman & Robin") loads the story with too many subplots and so many references to the series that he and director Stephen Hopkins ("The Ghost and the Darkness") ultimately lose their grasp on things.

Also, the story feels like a setup for the inevitable sequel, and as the payoff involving time travel is not only confusing, it violates some of the same scientific "laws" laid down early in the movie.

To their credit, most of the actors have fun (particularly Oldman, who makes a more vicious Dr. Smith than the show's Jonathan Harris). But the awful performances of TV stars LeBlanc ("Friends") and Chabert ("Party of Five") are a definite distraction.

"Lost in Space" is rated R for violent (laser) gunplay, alien goo and gore, profanity and some vulgar references and double-entendres.