These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: Jacques stands out as a stark contrast with his two Woobie, Destroyer of Worlds co-conspirators. While his partners had no idea that praying to their cat god for help in their pursuit of vengeance would lead to their transformation into monsters, Jacques was a normal man who willingly became a monster to make himself immortal. For years he's been using his ferry to escort people to Moonscar Island, only for him and his partners to drain the life from them. Afterwards their victims are left to wander the island as zombies, aware but unable to move on to the afterlife.
First Installment Wins: Oodles of direct-to-video Scooby-Doo films followed the success of this one, but few if any of them earned as much acclaim.
Fridge Brilliance: During "It's Terror Time Again", Scooby has fallen into quicksand, and Shaggy is looking for a vine to pull him out with. One of the zombies taps him on the shoulder and gives him one. Shaggy nods in thanks, realises who gave it to him, and skedaddles in terror. It looks exactly like one of the stock gags that Scooby Doo has used for decades. However, since the zombies are the good guys and genuinely are trying to help, this time the implausible behaviour is fully justified.
Lena claims that the tunnel under the mansion was dug "to hide from Union soldiers." We later learn this is not the case. But even before this, there's a few clues suggesting she's lying, if the island's history is any indication. It's so remote that it's difficult to get to even in modern times and is in a bayou that few people enter for any reason, so the chances of the islanders being visited by the Union Army with any regularity are slim. Note, too, there are fewer Union soldier zombies than Confederate ones, further supporting the notion that Northern troops rarely came there. From this, it can he gleaned that the tunnel was not dug for the purpose Lena claims.
Fridge Horror: One of the zombies was either an overweight woman in her previous or a pregnant one.
The "zombies as the good guys" revelation loses some of its impact when you remember that a goodly portion of them are in fact the pirate crew who murdered the islanders by forcing them to wade into the bog, where they drowned.
Fridge Logic: Velma knew Lena was lying about Simone being kidnapped as soon as they found her in the passage, so why did she and the gang go down the passage with her?
To find out where Simone had gone to. The Gang had no clue that Simone and Lena were behind it at all, or how.
Les Yay: Simone and Lena carry this vibe when you stop and realize how old they are and how much of their lives they've spent together. Lena may be Ambiguously Bi considering the way she flirts with Fred and mentions she "really did like him" before trying to kill him.
Magnum Opus: Thanks to the film's darker nature, tendency to lightly mock the formulaic use of the Scooby-Doo Hoax, and dedication of still staying true to the spirit of the series in spite of that, several Scooby fans and even non-fans feel that it's the best piece of media to come out of the franchise.
Misattributed Song: "It's Terror Time Again" by Skycycle doesn't have a full-length version, not even for the end-credits. The full-length one is attributed to Gary Falcone and Joe Pizzuco and is on the soundtrack album for Scooby Doo and the Witch's Ghost.
Moe: Well, ain't Lena just the cutest little Southern chick you ever did see? It may or may not be an act; we don't see enough of her pre-curse to judge what her personality was like back then, but she definitely uses it to fool people.