Quite good
Would had been better to had been named The Witcher: Castlevania.
Unfortunately the story is not as original as the Castlevania one, lots of stereotypes and the story is quite common.
The animation is amazing, fight scene pretty well done. The OST is quite close to the game music.
Overall I would agree with the IDMB rating.
PS: the introduction of black characters in medieval European setting was a bit off but there were pretty few and it wasn't as bad as in the show.