I give this four stars because I love Harry Potter and it kept me hooked until the end. I loved Scorpius and Albus, Scorpius more so actually. That being said, I was disappointed by a lot of different parts. The biggest thing that disappointed me was the lack of mentioning Hagrid (in the present tense), the complete ignoring of Teddy's (Remus and Tonks' son) existence, and the way they talked about Ron running Weasley Wizard Wheezes without ever mentioning George. They didn't need to pay actors to play characters that they only mention, all I wanted was a mention of these few characters.
At some points it seemed so much like a run of the mill time travel story set in the Harry Potter world, that it felt like a fanfiction, written in script form, which was really weird. The characters seemed to not have the original writers' mind behind their words and actions, which makes me wonder exactly how much JKR actually wrote, and if she was really just a consult for continuity purposes. Ron was basically comic relief which was annoying because in the books he actually has a personality. Harry would never ever say the things that he said to his son in this book, in my opinion, and he had none of the normal sass that he has in the books. Ginny was more spot on but I feel like that's because she never had a lot of personality in the books anyway.
I only loved it because it was set in the Harry Potter universe, the story and the characters were not done to my liking, which I assume is better when seen play out on stage, which I would still love to see. Draco and Scorpius were the best characters in it which was odd.
Basically when I finished it, I didn't quite know how to feel at all. I loved it and I was disappointed at the same time. I was glad to see the characters back as well as being disappointed in their portrayal. But again, it may be because I am not used to reading in script form, now I just feel like I want to see the play even more to see if the actors can counteract some of the things I disliked.