A great background, original idea, impressive effects and art direction. The family that rules part of the Universe looks pretty convincing, humans but above humanity.
But there is the story, the good characters and the dialog...
The shallow dialogs between Jupiter and her love pet becomes so incredibly annoying, that reminds of Twilight or any chapter from Dawson's Creek. Jupiter falls in love by smelling dog hormones and being saved.
She has no personality at all, only that wants a microscope, Mila was not able to create something credible from that. The wolf boy is as expressive as any furniture on your home. Pluto waits for her to wake up (12 hours!) to take her to the space ship, ofc giving enough time for the bad guys to find it and destroy it.
Action is forcibly extended and becomes repetitive, mainly the scenes for the last second remaining before destruction.
Design and effects are awesome, but... the giant iguanas looks not serious at all. Also, the cruiser crew celebrating like kids the saving of the good couple is lame and cheap.
Rewrite good characters and their dialog, improve the script, replacing the cheesy love story for something decent, and you have hell of a classic.