This takes everything the great first film did, adds a great new story, and creates a perfect sequel. There's obviously a lot of cheesyness (just like the first one and maybe it's just nostalgia watching a movie from childhood), but it works. The main casts performances are again spectacular, and Joan Cusack is a great addition as a "Black Widow" type of killer. They could've written off the Addams kids as a minor side story, but the camp scenes only enhance the evolution of the children's characters and are a key part of the joy of watching this film.
Both the Addams Family movies are great adaptions of old TV shows, although I have no point of reference to the original, since it came out decades before I was around. But most movies I've seen in my life of old TV shows (usually never even heard of the shows, let alone seen them) tend to be horrible. This one's a must watch.