If you ask me
You're pumping these out too quickly. Each one hasn't improved at all in animation and some of the most persistent complaints such as the awful sound levels/quality. It's really frustrating to see that, since episode one, the lip syncing animation has pretty much just stayed as "open mouth > half open mouth > teeth clenched mouth" on a loop roughly timed to the speaking. And in pretty much every cartoon of yours, there's always weird subtitle errors that aren't exactly what the characters said, too. I know it's a small complaint but it'd be such an easy fix to just rewatch the cartoon and check for mistakes.
I know it must be a pain/seem exaggerated to be told to stop/slow down making cartoons until you have problems fixed that essentially have nothing to do with you, but it really is painting these episodes with a coat of mediocrity right from the get go. The thing is that not a lot of your voice actors are actually that good, and I think it would be a wise decisison to get different voice actors on board for some people. I know you're getting the people the characters are based off of to voice them, but I think that this really matters only to you as an author, but to the rest of the viewing public, no one could care if you replaced the voice actors with better ones/ones with better quality equipment even if it meant it wasn't their "real" voice. This is just something I think you should consider, or just buy everyone some decent recording equipment (hey, it's christmas soon!)
I think this is probably the most poorly paced/unfunniest episode of the lot, with the worst story. I mean it's almost like it just abandoned the main plot point of them finding a halloween costume for Rat about half way through, which was pretty bizarre. I think it's probably a good idea to not base your stuff on old comics from 2003, maybe. For a halloween special, it sure didn't feel like it was very much halloween related at all except for that zombie...and I really have no idea what that's about. Maybe you/your friends do because it's some weird kind of injoke, but as a viewer I just felt um...left out? Yeah, sure.
On another note, I find it confusing how you seem to value this series much more than AE Chronics, which is more original (though still seems overly silent hill inspired) and better paced/written than this. I honestly think humour isn't your strong point, at least not when it's based too much on insider jokes from years ago.