The dialogue is pretty bad/cliche but I guess thats a staple of the genre. Everyone talks in the same jingoey rowdy American sounding way and it's kind of hard to believe the setting is supposed to be medieval Romania.
There's lots of incoherences too. The show is unapologetically anti-religion or anti-Christianity at least (main characters declaring themselves enemies of God) yet these same characters seem to utilize very Christian tools (holy water, crosses, etc) to vanquish demons? Not to mention it doesn't really go into any real depth on the matter of religion or its historical relevance in that region in that period. But I understand that that wouldn't sell and scapegoating organized religion is easier and more palatable to western audiences. Which is a shame because the games did at least try to explore it.
Also, the sex stuff in S3 really comes out of nowhere and is really shoehorned into the plot without any real reason. It's just really weird.
Its not a bad anime but I wouldn't say it's very good either