First of all: this review does not contain spoilers. Still, I'm writing about some characters that are in the book and some small parts of the plot (without too much details). So, if you want to start this book knowing nothing about it, I advise you to come back when you'll be done with the book.
I found this play brilliant. I insist on the fact that it is a play and should be considered as such. Many people were disappointed by it, because they expected a Harry Potter story. I assure you, it is not. If it's what you expect, I advise you not to read this script. (People may have been disappointed for other reasons as well).
First of all, I don't have a lot of knowledge on playwritting. I studied it a bit at school because it was part of the cursus, I really enjoyed some Moliere (yeah, I live in a french-speaking country, Shakespeare was not part of the program *shame*) and I found theatre really amazing. Still, I have never read a Shakespeare (yet) and I don't know a lot about the convetions and rules of playwritting. All this to say, I'm not an expert.
I'm not entirely unbiased here, I mean it's J.K Rowling and it's Harry Potter's universe. I've been dying to have more of this universe for a really, really long time. However, i'll try to do my best and write a review as honest as possible.
I totally enjoyed the weird situations where I thought "it would not happen in Harry Potter", but of course, I say it again, it's not Harry Potter. It's not a novel, the dynamic is entirely different and I love it for that. That's what got me the most, the dynamic of it, the weird situations where the characters were really different from their Harry Potter self (Draco and Ron are so, so different), but it was brilliant! I adored every second of it, I enjoyed discovering old characters under a new perspective.I loved seeing what they've all become years after we left them in Harry Potter and The Deathly Hallows. And the best was experiencing old scenes from Harry Potter, but differently.
Don't get me started on the new characters, Albus is amazing. Albus is what Harry should have been for me to like him (don't get me wrong, I don't hate Harry, he's just so annoying at time). Yes, Albus also made huge mistakes, but he is honest and true to himself. He looks like Harry without being too much like him. I really enjoyed meeting this new character and I wish I could have more of it. Scorpius was also really interesting and so funny (most of the time, despite himself. I love this kind of people). I love the alternate reality in which they end up due to some magical stuff happening (you'll see, you'll be amazed by some encouters with old characters. At least, I was), I found this really brilliant and so much fun to read.
I also almost cried at the end because it was over. Because one of my favourite character of all time made an apparition and although it was in a really famous scene from Harry Potter (nothing new here), it was so sad to know it was really the end. I wish I was able to see this play. Seriously, I'm dying to see this.
Ok, this was as honest and as detailed I could do without spoilers. I hope some people enjoyed it as much as I did and for the one who did not, well I'm sorry. I also totally understand why some people would not want to read that. Harry Potter's story is over and maybe, it should stayed that way, but I'm so glad I could have a glimpse of this universe one more time. It was such a good journey!