The biggest flaw in the sequel is that is isn’t actually a sequel at all, but a completely different horror comedy rewritten to mimic one. While this is not unusual at all (as is the case with House III and Halloween III for example) it does set the viewer to a wrong mood to begin with, only to get something completely different than anticipated.
Viewed as a completely separate entity, Bud the Chud is actually not that bad.
There are a few actual laughs every now and then, and the showdown in the swimming pool is pretty unique. It’s just the amazingly strong competition of the late 80s horror comedies that make it look bad: Compared to the likes of The Lost Boys, Return of the living dead, Night of the creeps or Beetlejuice it’s just totally forgettable.