First off, Cloudy with a Chance of Meatballs (the movie) is almost nothing like Cloudy with a Chance of Meatballs (the book). I have never particularly enjoyed the book; I really enjoyed the movie. My husband loves the book (and anything to do with weather); he loved the movie. This is one of the very few instances when you'll hear me say that I liked the movie more than the book...
The book version of Cloudy with a Chance of Meatballs is a story told to two children by their grandfather and, in my opinion, it's kind of dull and more than just a little anticlimactic: the big food comes, and everyone leaves the island, never to return.
The movie version of Cloudy with a Chance of Meatballs is so much more! The writers kept only the basic concept (food falling from the sky) and liberally applied creative license to result in a cute and downright funny movie: Flint Lockwood is an inventor who can just never seem to get his inventions quite right: the remote control TV that walks out the front door, ratbirds, spray-on shoes (to solve the untied shoe epidemic, of course). He invents a machine that turns water into food, which accidentally gets launched into the sky above his hometown, showering the town with food.
My husband and I both thoroughly enjoyed this movie, as did the in-laws. I was excited to show the movie to my nieces, ages 4, 6, and 7, thinking that they would laugh through the movie just like all of us [grown-ups] had. To my surprise, they didn't laugh at all. Not once. They enjoyed the movie, but they really missed out on most of the comedy and, in some places, had a hard time understanding what was going on.
Final word: B+. A great movie, which we will buy. Best for older audiences, probably 10 and up, who will understand the humor.