Strange... or drab... or something...
The best way I can describe what I felt about this Flash is to compare the animation and drawing style to one of the moments in the video itself. The one where the boy is explaining to the character "Doggy" the following things about how Halloween shouldn't be considered a holiday anymore:
1. The PRANKS are lame
2. The movies are all over-used, etc.
3. The PRANKS aren't brutal or fun
The explanation about his feelings involving the pranks is introduced 2 times... as if the second time is some different point he is making. It sets the tone for the rest of the movie, I feel, where some of the animation didn't make much sense, or was really lamely tied to the Nightmare Before X-mas theme, with un-inspired drawings and sub-par animations.
One of the really confusing things was the character expressions. What feeling is supposed to be conveyed by zig-zags for pupils? How about entirely flesh-tone colored eyes? The eyes of the main character were a mess during half or more of the entire Flash.
It seemed like a lot of work went into this... but the characters don't seem to be anything special or original really, to have warranted the amount of work that you are willing to put into their contuinued use.