Ah sorry about that, sometimes old links go down and I forget to check on them. Honestly, there is next to nothing changed in the original halloween hack. I literally did that one in an afternoon when I was bored, it doesn't have changes on the scale of the christmas hack.
All that it has changed are:
-added jack-o-lanterns and dead leaves to tileset
-added ghosts to most routes at night
-starter pokemon know their first special attack from the start (so they can fight ghosts)
-a small abandoned cemetery is added near Ecruteak, with an event to battle Aerodactyl
-Aerodactyl is Ghost/Rock type (if I remember correctly).
-maybe one or two text edits
Not a lot done haha. But if you really want I'll send you a link to it.