It is just too much of the same thing. Greg who never grows up, tries out new things, gets in arguments or something else with Rowley, more about his very weird family and so on, and so on.
For me, this series is now dropped, I just feel like the first few books were good and interesting, but for me nothing changes between the books. Sure the characters get older but that is really everything.
I really disliked Greg in this one, especially at the beginning, but also at other parts. He is jealous of Rowley, and he kept whining about it the whole time. I already didn’t like how Greg treated Rowley (instead of a friend, I felt that Greg was treating Rowley more as an accessory, so he becomes more popular, or as a slave/lackey who will do anything for him. You can also see that in this book. Two times you see Greg being all rich and grown-up and Rowley either have no friends or he is the gardener. I think that is just sad, that is not friendship at all.
Greg later tries his luck with an 8-ball, and while it was funny at times, I was also shaking my head many times. I am not sure how old Greg is, but I would say somewhere between 12 and 13 and by that time I may hope he can make his own decisions and think for himself and not needed some sort of toy and follow that one no matter what.
Another thing I found strange was how lunch went in Greg’s school. There are not enough seats so people have to sit/stand in the hallway or against walls? Wait what? How does that work and why does the school take no effort to get more seats or at least divide the lunch period some more.
We also meet more of Greg’s strange and weird family. Are there any normal people in his family?
But all in all, it was just too much of the same thing and again, Greg just annoyed me to hell.