I think the movie was overall good. It was one of barbies better works but it definetely has its down sides.
For one thing, background characters. They used to have one common mold for insignificant characters all repainted differently. They changed the molds for everyone. Barbie and her human friends had classic shapes. But her mermaid friends, including kayla and xylie, all look exactly the same. Just repainted. And i am not too fond of the feminine mermaid mold they used. I also dont like how they focused more on fallon and made hadley look like an idiot. Another thing, barbie, ever since the princess and the pauper, has been using those same names for massive numbers of succeeding films including names like janessa, fallon, an hadley. I am also not too fond of merliahs name, but her new face mold was lovely.
The music was all good but there is one thing that isnt a flaw, but i definetely cannot stand. Merliah's fake mermaid costume with the beautiful color mixes looked better than her flowery, pink mermaid form. They dont even have flowers in the ocean! Also, i think the destinies should have been more mystical than fashionista shop owners.
Other than that, it has a decent plot, decent characters, realistic animation, and is a film worth watching.