Nostalgia aside, the biggest challenge for this animated movie -- lacking the novelty of the live-action versions produced in the early part of this century -- is layering a feature-length plot over the bones of a formulaic Saturday-morning cartoon.
The film at least mostly meets the challenge on that level, casting Shaggy (voiced by Will Forte) and Scooby (Frank Welker) at the center of a threat to the entire world, as they're whisked off by a superhero known as the Blue Falcon (Mark Wahlberg) on a big, messy adventure. There's also a telegraphed message about the importance of friendship, testing the seemingly unshakeable bond between the central duo.
Directed by Tony Cervone, "Scoob!" tries to adopt a contemporary feel, with a cameo by Simon Cowell and references to such things as Netflix and Supreme Court Justice Ruth Bader Ginsburg -- the latter chosen by the Scooby gang's Thelma (Gina Rodriguez) as her Halloween costume.
In terms of voices, Zac Efron and Amanda Seyfried round out the group as Fred and Daphne, respectively, while Jason Isaacs (Lucius Malfoy in the Harry Potter films) sounds rather uncannily like he's channeling Hans Conried (the voice of Captain Hook) as the villainous Dick Dastardly, a sneering bad guy from the Hanna-Barbera stable, now with an army of robotic (lower-case) minions.
Other than an introductory sequence that depicts how the key characters met, there's not much new to flavor the action. Scooby does speak a bit more clearly than usual -- which is kind of creepy -- and there are clever moments, such as a fleeting game of Whac-a-Mole, as well as winking reference to the Hanna-Barbera franchise's long history, including a venue named after original Scooby voice whiz Don Messick.
That's about as inventive as things get, and beyond the improved computer animation compared to the hand-drawn origins, sequences worthy of attention are too few and very far between.
Granted, "Scoob!" appears more into recycling than reinvention -- it's more a snack than a meal -- but it does endeavor to make an old concept fresh and cool again in children's eyes. That might answer the question why the movie exists, but based on the results, nothing here merits an exclamation point.
"Scoob!" is available for on-demand rental and purchase on May 15. It's produced and released by Warner Bros., like CNN, a unit of WarnerMedia.