I couldn't bring myself to finish the whole movie, though normally I don't mind the harmless fun of these.
This movie feels like a fan-fiction that was written quickly and the animation reflects a lot on the overall feeling that this movie was never intended to be more than some harmless fun for an hour. While the characters do look like the toys, I found the bucket-fill colors to be very straining on the eyes at times.
Despite the title having "Barbie" in it, the main character is called Kara. She's a princess and one day gets kissed by a radioactive butterfly and gains superpowers. Then not much happens in terms of plot. Occasionally she rescues some people, but mostly it's flying through the skies with pop music playing. There seems to be no focus as to what the plot should be. Things just seems to happen so that Kara can react to it. We're introduced to a villain at the start of the movie, who does have a clear motive: He wants the kingdom instead of Karas family. After 10 minutes of screen-time, this character simply vanishes. After about 40 minutes of pop-music, flying and random rescue scenes, he is back again. Only to disappear again for some more scenes about the superpowers and harmless interactions with Kara and her friends. And then he returns a moment and then back to harmless.
It's not a horrendous movie, so I can see little girls liking it. I don't think I hate anything about the movie, I just don't feel it's as engaging story and character wise as Disneys "Tinkerbell" movies.