(Fair warning: This review may contain spoilers!)
I really enjoyed the first Castlevania series on Netflix. I felt like it did a fine job of telling the story of Castlevania in general, explaining the events of 3rd game in a way that wasn't perfect but acceptable enough that it could potentially lead into the events of Rondo of Blood / Symphony of the Night (which as most are aware are the two of the biggest installments in the series).
Nocturne was a bit of a disappointment in my opinion though. If I had never played the games, this probably wouldn't be the case. But, since Richter Belmont was involved, I was hoping that surely good things would come from this.
As a hardcore fan of the games, it's pretty apparent Nocturne isn't canon. So, I guess just don't go into it expecting as much.
You'll find lots of familiar faces: I was glad Olrox was in there, and Maria. But, Anette, for example, isn't at all who she was in the games.
There's still potential in future seasons of Nocturne, but, because of the way things played out, it's going to pretty much be impossible to tell the original story of Rondo of Blood / Symphony of the Night at this point. So if that's what you were hoping for, lower your expectations.
For anyone enjoying the show for the drama, action, gore and occasional witty comment, or just because Castlevania is involved, this one still holds up. But, again, the writing wasn't at all what I was expecting as a pre-existing fan of Castlevania, and I was still holding out some hope about half-way in.