Time Out says
Mumble (voice of Elijah Wood) isn’t fitting in with the rest of his Emperor penguin colony. His father, Memphis (Hugh Jackman), mother Norma Jean (Nicole Kidman) and the commanding elders are bemused by the misfit chick’s propensity for tap dancing when, in fact, he should be breaking into song. But Mumble’s first attempt at singing is a tuneless disaster, and the forlorn penguin is soon ostracised for bringing a curse upon the colony. Seems the penguins’ fish supplies have dwindled alarmingly, and Mumble’s taking the rap. A short adventure later, he chances upon a troupe of rhythmic Adelie penguins, fronted by Robin Williams’ rockhopper, Lovelace. Lovelace has a plastic six-pack ring around his neck which he believes was bestowed on him by aliens. It’s at this juncture the film veers away from its cute, gloriously lighthearted song-and-dance routines – with covers of The Beatles, The Beach Boys, Stevie Wonder, etc – to embrace a much darker tone, where initial intimations about social mores are replaced by an effective, soul-stirring environmental message.
Young kiddies may find a couple of near-death experiences with a sea lion and an orca a little too frightening to bear, but that’s only because the standard of the animation is so outstandingly realistic and so acutely detailed. Director George ‘Babe’ Miller has pulled off a coup with this one; he’s raised the benchmark to a whole new level, both visually and conceptually. Bravo.