Great movie, plot follows, comedy is hilarious, and overall entertaining for both kids and adults, even if most of the jokes are for kids. First of all let me just get the "parent" things out of the way.
Violence: most of the violence is played for laughs (bar fight), however some violence is key to the story\ plot (such as Dennis being killed twice, but the way he dies is partially for laughs with no real emotional, or reality impacts). And there are "people" skulls visible. While also having, slapstick humor, along with peril that isn't very mild. Various black, swollen eyes are also shown.
Scariness: Cute, but also creepy monsters are a minor part. Plankton turns everybody into slaves (funny slaves at some points)
Sex: Patrick wears fishnets, Mindy does have mild mild cleavage, and Patrick has a crush on Mindy and calls her "hot". Pat's underwear is shown, Spongebob's butt is also shown
Beer: Fish are drunk at a bar, Spongebob\ Patrick becomes drunk off of ice cream.
Positive stuff: Kids will learn to be themselves, and try to accomplish things even if people put you down, along with having to learn to be responsible. Mindy is a VERY good role model even though she steals a "magical bag of winds" from her father. Spongebob, and Patrick never used violence to solve their problems, instead they use kindness, and determination, and occasionally wits.
Overall, this movie will entertain kids along with parents. There isn't really anything to worry about, besides violence, alcohol, and crude humor. However, for your child to actually laugh, they must be aware of what is going on, because the movie is mostly targeted towards 10 to about 16 year olds (I think). The plot does make sense, and isn't just a bunch slaps for laughter. There are also minor twists, hilarious surprises and dialogue, and surprising heartfelt and suspenseful moments. Even though this movie is a cartoon, it will be remembered as an unforgettable classic. Well worth money, however i wouldn't watch it more than once every other day.