I wasn't expecting a lot from the movie since I loved the book when I was a child and, as I recall, there isn't much of a plot to it. Surprisingly, the movie is quite good. The writers managed to take the thin book and turn it into an intriguing story with believable, yet funny, characters. Not only were the characters awesome, but the animation was also very good. Most people, nowadays, are looking for cutting edge "realistic" animation. While "Cloudy" isn't particularly cutting edge, the animation is clean and, to put it simply, pretty. The cherry on top is the crop of recognizable actors that were brought on board to give life to the characters. (My favorite is Neil Patrick Harris as Steve the monkey.)
"Cloudy" is definitely a must-see movie. The kids will enjoy it and I think the adults will love it as well. Good fun for everyone!