***THIS REVIEW CONTAINS SPOILERS!***
Pros:
This movie was short and I guess somewhat entertaining to watch.
Cons:
It made no sense.
Other people have already stated this but the fairy godmother being the same age as Cinderella doesn't make much sense. Neither is the fact that Cinderella is even allowed to go to school. You'd think that Lady Tremaine would keep her at home since she wouldn't want Cinderella making them look bad. Also, Chad is supposed to be the son of Cinderella, which doesn't make sense with how he's white and Cinderella and Prince Charming aren't(genetically speaking). He was likely either adopted or maybe there are different versions of Cinderella, similar to Once Upon A Time.
It felt like a lot of things were left unfinished and characters made strange choices. For instance, how come Cinderella's daughter got over Red basically sentencing her mother to death so fast? Also, they agreed to team up surprisingly quickly.
This movie expects people to believe that the Queen of Hearts went from sweet and innocent to an absolute tyrant... because of a prank. I get how that could be mentally scarring, but it doesn't quite warrant the little 'off with their heads' personality every time something goes wrong. It's possible that she went through bullying after that, but either I missed something or it wasn't really explained.
Why in the world did Uma think it was a good idea to invite the daughter of a known tyrant, basically inviting the tyrant herself, to a school that's made to be peaceful? I understand that she didn't want another VK to be trapped away, however, if Red didn't have that time machine, chaos would've ensued and there would've been plenty of deaths. I mean the Queen of Hearts has a reputation for being insane and a murder hobo, how could she not see it as a potential threat? Uma should've at least requested more security or something.
The overall plot was lackluster. The main threat was resolved extremely easily and it just felt... eh. The main characters have such bright colors it's weird that we don't need that much brightness(please, my eyes are burning). Red would've been fine with black hair. Also, you're telling me that the bullies didn't try anything else? They just got punished and never tried going after the Queen Of Hearts again? If the Queen Of Hearts never became a tyrant, then why didn't Red(upon coming back to the future) change to fit what would've happened? Time travel movies rarely make sense, and this one especially didn't. There was that cryptic warning that changing the past could have unimaginable consequences or whatever that didn't deliver, it seemed like nobody even cared what could've happened if they messed up a little detail. This movie was just so... kiddish. No real consequences, no real threat. I thought Descendants was a series marketed towards preteens and teens, maybe even older kids, so why was it so flat?
All in all, it wasn't terrible, but it definitely needs a lot of improvement.