I think this movie got a litle boring, but in the end it's ok.
There's not much violence except when Mumble gets attacked by a Seal, but there is sexual innuendo. I think it will go over young childrens' heads, but older children will ask about it.
Other reviews have said they were siging "Sex, baby", but they were obviously singing "Eggs, baby".
The macaroni penguins introduce a lot of sexual innuendo to the movie, like when one does a pelvic thrust, and when the all-known penguin goes out of sight asking "Who's first?".
I think this movie should be rated PG, but if it went just a LITTLE more over the line, it should be rated PG-13.
All-in-all, this was a good movie