The actor who played Zack in the 1st season was engaging and played a likable character. In the 2nd season, his replacement's interpretation of the character isn't at all likable. Of course, the story would need to show changes in the character's personality due to the trauma of seeing his mother as a strigoi, so that needs to be expressed. Still the new actor, Max Charles, isn't as good an actor as the 1st season's Ben Hyland.
Ben Hyland is playing a boy about 10 or 11 years old, while Max Charles comes across as a rebellious 13 or 14 year old teenager. His facial expressions are off-putting and his version of Zack differs greatly from the character that Ben Hyland portrayed in his interpretation of Zack.
The story is staying true to form with the flashbacks being identified as to time period and location. That helps keep the complications manageable. I do like the way the politicians and bureaucrats are shown to be semi-villains as well as being the slimeballs that so many of us see that type of character to be in real life.
I'm enjoying the writing by delToro, knowing that he won't be writing the 3rd season due to the author's disagreement with the showrunner. I haven't bought the 3rd and 4th seasons on dvd for that reason.