I liked Castlevania: Nocturne. It has highs and lows though. The setting being changed from Transylvania to France makes thematic sense given the new Castlevania games (specifically in Aria of Sorrow and Order of Ecclesia) themes of autonomy and resistance though it was anachronistic.
Annette being recast as a freed Haitian slave, while being radically different from the canon of the games, fits perfectly with the above mentioned themes of autonomy and rebellion. I think it's better than how in Rondo of Blood OG Annette was treated less like a person and more like a plot device, since saving her unlocks the canon ending.
The negatives are few but I found Annette's actions in letting her companion Eduwar follow her into active combat, when he is a civilian without any combat experience or magical power to be a poor choice on Annette's part and a ham fisted way of generating tension on the writer's part.
Also, It would have made more sense for Maria to speak with a French accent given the change in setting.