Look, it's Scooby-Doo. You know exactly what you're getting: a safe, formulaic mystery with ghosts that turn out to be people in masks, some Scooby Snacks, and a "meddling kids" punchline.
The problem? Even by Scooby standards, this one's pretty weak. A 42% audience score and 5.9 IMDb rating tell you that even the die-hard fans weren't thrilled. The doppelgänger concept could've been fun, but it's executed in the most paint-by-numbers way possible.
That said, if you've got a 5-7 year old who's obsessed with Scooby and wants something Halloween-adjacent, this will do the job. It's safe, it's short, and it won't make you want to claw your eyes out (just maybe check your phone a few times). But there are better Scooby movies out there if you're picking from the catalog.