"Serenity" is Joss Whedon's tying up of loose ends following the shameful cancellation of the "Firefly" TV series. "Serenity" has less of the wonderful world Whedon created for "Firefly", and has less of the character interplay and evolution that "Firefly" had. That's inevitable.

But as a chance to see the "Firefly" saga completed "Serenity" is invaluable. There are strong performances in there, better appreciated if one has seen the "Firefly" series first of course. The world of "Serenity" isn't as large as "Firefly"'s which range from Wild West cattle ranches to high-tech spaceships, but is still fascinating.

"Serenity"'s story arc focusses on River more than Mal, and becomes her redeeming her life. Whedon toys with the viewer at the climax of the film, allowing him as director to have his cake and eat it. Perhaps more a tribute to the "Firefly" series than a standalone film in its own right, but still an enjoyable SF movie in which right triumphs over wrong.