Absolutely terrible. They throw everything from the first 7 books in the trash. Harry tells his son, albus, that he wishes he wasn't his son. That's not Harry Potter. They turn Ron basically into a drunk. The worst character though had to be the trolly witch. I mean what where they thinking on that!? They basically turned her into a demon of some sorts, put on the train for 200 years to stop students from leaving. And she says she was able to stop James, Sirius, and lupin, along with Fred and George, but couldn't stop albus and scorpius? That doesn't sound right.
The script also had a lot of lazy writing. Like albus and scorpius get stuck in the past and have no way of getting back. It's like the authors realized this, so they bring Draco in and he's like, oh hey, I just happen to have have this illegal time turner we can use to save them. What? Like at least give some background or something. This was not a Harry Potter novel and I'm sorry, but I'm not treating it as Canon. Just leave the 7 books as is and nothing else.