Sophie comments that everyone in Halloweentown looks dressed for a party, until Aggie explains that their usual appearances inspired several mortals' Halloween costumes. Perhaps Sophie's comment handwaves any creatures that by post-1998 standards, look obviously like people in masks.
In the second movie, shouldn't Marnie, Aggie and Luke have more time to work out their subplot, since time goes slower in Halloweentown? But at least in the present scenes the whole world is under the Gray Spell, which could be "normalizing" all magic, including the time difference.
The word that Kalabar's Revenge uses to activate the Grey Spell, "apart", really does appear nowhere in the dialogue of Halloweentown, not even with a space separating the first letter from the others.
Fridge Logic
How exactly did Gwen and her late husband's romance work? They met at a Halloween party...and then had their second date a year later? Or did Gwen get stuck in the mortal world by accident and just decide that she liked it? Did they meet year after year, just elope on a whim, what?
Despite being Weakened by the Light, Kalabar can walk around in broad daylight with no issues at all.
It might be that Kalabar only has that weakness when he's channeling the powers of darkness. Or perhaps the hat he wears all the time gives him enough darkness to get by.
So how does Marnie look completely different in the fourth film, and is still recognized as Marnie?
As a witch with all her powers, Gwen has a lifespan of 1000+ years, yet in the first film she's bound and determined that all of her children are going to be regular humans. This means that she would stay relatively young while her children grew old and died, and she knows it. Maybe Marnie wasn't off the mark with her jab about Gwen getting tired of her kids and disowning them eventually after all.
But on the other hand, she's presumably aged fairly significantly her +10 years in the mortal world...right? Wouldn't people eventually notice if she didn't?
Not entirely sure if this is what the previous person was getting at, but maybe being in the mortal world (or possibly, not doing magic) makes her age like a mortal would. Also, maybe the reason she doesn't use magic very often is because she doesn't want to live for centuries more without her husband?
The idea that being in the mortal world shortens lifespan directly clashes with Aggie's being just fine. It's been established that the only thing that could impact it is your capacity for magic being removed, not lack of practice of it. So Gwen very likely is just using ordinary if expensive makeup to appear a little older as some people really don't visibly age much in +10 years, even if she didn't want to use magic to glamor.
The second reason could still hold though - Gwen not using magic could be why she aged.
How old was Gwen when she met her husband? She crashed a Halloween party, but she could have been anywhere from late teens/early twenties to centuries old. Mayfly–December Romance, anyone? And if she actually does have a 1000+ years lifespan, then she knew going into it that her husband would die long before her, too.
If it makes it any better, the lack of mentioning and angsting over it seems to suggest she's come to terms with it.
Perhaps she only even meant the non-magic time to be a fanciful phase to prove she can do it before moving on to what awaits her next in life. Albeit, that can again put a bit of a dark light on how she views the children that resulted from the coupling, at least at first.
For a supposedly good witch, Aggie has a couple of less than savory spells in that book of hers. (The Grey Spell and the Creature Spell, for example.) Kinda makes you wonder if there was a time when her use of her powers wasn't so benevolent.
Of course this was confirmed in the fourth movie.
Confirmed in the first movie: Humans and monsters were at war when Halloweentown was created. Aggie would need spells to defend herself with for good or bad.
Which could also be explained as knowing the spells with the specific purpose of being able to defend against them if used.
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