...this movie isn't that bad, long as you keep in mind that (even after it was "softened up" from its first draft) it's not actually a straight up Scooby-Doo
story, but more of an Affectionate Parody
of the franchise. It pretty much takes all the classic Scooby tropes and frequent fan theories ("wink-wink-nudge-nudge, Shaggy's a pothead"), and mocks them for all they're worth. Which kiiiinda doesn't work in the movie's favor because that means it upsets the dedicated fans who were hoping for a more respectful treatment, and people who didn't like the old cartoons, who would probably appreciate the mocking a lot more, aren't going to be interested in a Scooby-Doo movie to begin with. So basically the only people the movie appeals to are people like me, who liked the original franchise more in a So Bad, It's Good
way. And I'm not sure how many there are of us.
A pity, really, because once you get behind the obligatory and groan-worthy gross-out jokes, as a parody this is actually pretty solid stuff. It has some good performances (Matthew Lillard being the standout as Shaggy, no wonder he's the one voicing Shaggy in cartoons nowadays), a very convincing if somewhat disturbing CGI Scooby, a suitably terrible mystery with some appropriate red herrings, and it plays enough of the formula straight to make the parody bits work better... plus the twist ending was genuinely surprising and in my opinion extremely funny.
Yes, I will say it, this movie made me an unabashed fan of Scrappy-Doo. I know he's supposed to come across as annoying and unlikeable here, and lots of fans have spoken against the movie for the treatment of Scrappy, but... I can't help it, apart from that one disgusting "marking his territory" joke, that pup is just hilarious
here. First time I saw this film I nearly fell out of my seat laughing whenever he was on-screen.
All in all, I think it's the utter refusal to take either itself or its source material seriously that makes the movie work as well as it did — the sequel, which played the Scooby formula a lot straighter, wasn't anywhere near as much fun.
Oh, and the deleted opening, with animated credits and a pretty nifty reggae-style remix of the first theme song of the cartoon, is probably one of the best deleted scenes ever and should have remained in the movie.