Dracula. Some applaud the return to focus on Dracula's genuine monstrosity after modernity's turn towards making vampires into harmless smoothed-over romantic interests. Others see it as the complete opposite, a continuation of the many adaptations that try to fetishize a character who is basically sexually predatory behavior personified into someone cool and desirable while trying to excuse the character's monstrous behavior through his tragedy. Some see this issue as being further compounded by inconsistent characterization, since at the very end of the show Dracula suddenly kills himself, because...he is really sad, and full of shame....and wanted to die all those years. In these fans' view, this doesn't gel with anything in previous episodes and seems to most viewers to come out of the blue, ruining character and the whole premise of the show.
Agatha Van Helsing, for many reasons. Some fans liked the idea of Dracula's main adversary being a competent and intelligent female Van Helsing and liked the angle of two battling and opposing equals with a major helping of Foe Romantic Subtext added in. Others on the contrary didn't like how it played out, since the whole Gender Flip of Van Helsing seemed to serve the sole purpose of this Foe Yay Shipping and showing Dracula and Agatha/Zoe having sex in dying-dream-sequence at the end of the show. Still others were frustrated, because gender-bent Van Helsing ultimately got killed off in the show, first as Agatha, then as Zoe, while the original male Van Helsing in the novel was very much alive and well after his encounters with Dracula. Still more felt like her character, while generally enjoyable, left a bitter taste with them due to how it contributed to the They Changed It, Now It Sucks! and They Wasted a Perfectly Good Character issues, arguing that the writers gave Agatha (and Zoe) a lot of roles and traits that originally belonged to the novel characters who got pushed aside or retooled so Agatha (and Zoe) could stand in their places as Dracula's competent adversary.
Captain Obvious Reveal: The way Jonathan Harker looks and acts during his time at the convent makes it clear as day he's undead himself long before the narrative makes it official. It's more a question of how, not if, he ended up in this state.
Fanon Discontinuity: Viewers are severely divided over whether the Time Skip and the events that happen thereafter were a good idea, to the point that some have suggested that new viewers only watch the first two episodes and skip the third.
Foe Yay Shipping: Between Dracula and Van Helsing. To the point that the two are shown having sex in a dream, while dying in reality. It doesn't help that making Van Helsing female seems to serve the sole purpose of of this Foe Romantic Subtext and showing this particular scene at the end of the show.
Many viewers saw the whole Dracula/Agatha/Zoe Van Helsing dynamic, banter and mannerisms as Moffat and Gatiss rehashing the same "battle of the ubermensches with Foe Romantic Subtext" dynamic from their many previous series, most notably Sherlock, and thus didn't find Dracula vs. Agatha to be interesting or creative, but redundant. Their dynamics were even labeled as "Dracula just being Moriarty with fangs and Agatha Van Helsing just being Sherlock with a cross".
Likewise making Lucy an antagonistic character had many Dracula fans pulling similarities to the 2013 live action version where she was likewise written to be in an antagonistic role. note This likely stems from the '92 Dracula movie, which wrote Lucy as being more flirty, which in turn has kinda painted the character as this in later adaptations. In the novel, she was nothing like this and was one of the sweetest characters of the book.
Midway through the first episode "Rules of the Beast", Dracula has Jonathan at his mercy and offers let him go if he swears not to try to stop him. Weakly, Jonathan says "I promise... I will do EVERYTHING in my powerto stop you!" This is such an epic moment of the human spirit that Dracula even chuckles rather admirably "Of course you will. That's my Johnny."
The entirety of "Blood Vessel". The episode is exactly what Dracula fans have always dreamt of: a story that centers around the mystery and horror of the Demeter, almost as though "Alien" and "Murder on the Orient Express" got on a boat and had a baby.
Dracula utilizing one of the vampires' little known ability and manipulating the weather around the Demeter to perpetual fog.
Yamini using the sign of the Cross to repel Dracula proves to be pretty resourceful.
After Lucy's funeral, her bereaved mother swears she can hear and feel her daughter crying out to her. Cut to Lucy in her casket, screaming as it catches on fire. It's meant to be Dramatic Irony, but it's so abrupt and on-the-nose that it might just make the viewer burst out laughing.
Dracula feeding from someone can apparently cause that person to become obsessed with him. Zoe is so fixated on him that she makes the wifi password his name, while Renfield fills out every answer on crosswords as "DRACULA".
Older Than They Think: This is not the first adaptation to kill off Jonathan Harker near the start and then make Van Helsing the protagonist: the same thing was done in Horror of Dracula, with Harker even becoming undead because of it (though there it was ultimately Van Helsing who killed him rather than Dracula). Likewise the Dan Curtis 1973 version and the 2012 Dario Argento version also did this as well (Harker getting fed on and turned by the brides in the former version and getting bit by both Dracula and his bride in the latter. In both near the end of the movie, he ends up getting staked).
Squick: Just about every single scene where one of Dracula's victim's fingernails peels off.
The fly landing on Jonathan's eye and crawling under it can evoke this.
They Changed It, Now It Sucks!: A number of deviations from the original source material proved largely unpopular with fans of the novel:
In the novel, Jonathan's love for Mina and determination to subvert Dracula's plans empowers him to eventually reverse the power dynamics on Dracula and successfully behead him in the end. A far cry from Jonathan Harker's ending here, in which he is not just killed off and made undead himself, but by inviting Dracula into the convent is made complicit in the massacre of the nuns.
Mina Murray/Harker is demoted from the main heroine of the novel to nothing more than a brief supporting character, becoming Adaptational Dumbass and Screaming Woman with ultimately no real significance to the plot. Her main heroine status and some of her functions in the plot are given to female Van Helsing.
Many viewers in general weren't happy with the explanation that all the vampire weaknesses of Dracula were simply a product of his own imagination and weird neurosis and that Dracula so abruptly and easily kills himself as soon as he is called out for being a coward.
Mina Harker. For a character that is central to the novel's plot, Mina has a brief cameo dressed as a nun in Episode 1, fends a vampiric Jonathan off with a sword, and swears to avenge his death and destroy Dracula...and then disappears for the rest of the series.
Jonathan, after episode one. In the novel he and Mina are the main protagonists who stand against Dracula right through to the end of the novel, and their devotion to each other serves as a thematic point of contrast with the villain, a monster that "can't love"; in this series most of their importance (aside from the inciting incident of the plot, Jonathan's entrapment in Castle Dracula) is given to the female Van Helsing, and they're discarded as characters after her role as Dracula's new adversary comes into focus. This is especially strange given how much of episode one is dedicated to developing Jonathan's character and drive to oppose Dracula, only to discard this drive at the end and replace him with a protagonist viewers are much more divided on.
The first two episodes made it seem like the series was going to be an episodic retelling of the novel, which largely intrigued audiences. Then the third episode came and punted the story into the present day which, while interesting, robbed of the mystique of it for most viewers.
It's not uncommon online to find viewers who would have preferred the series followed the newly-undead Jonathan's continued attempts to stop Dracula while struggling with his own vampirism, rather than the show killing Jonathan off completely at the end of episode one in a manner that was divisive among viewers at best. Often they also mention involving Mina more.
Agatha Van Helsing hints at a complicated relationship with her faith during the first episode, even rejoicing at the revelation that Dracula was repelled by the cross, since it's a tangible sign of the existence of God. This is then completely forgotten, her background and issues with faith are never further explored and she spends the next two and a half episodes as a nun that doesn't believe in God. Making you wonder what was the point of making her a nun instead of a doctor in the first place.
Given the changes from the original novel and the shift in timeline that starts episode three, a fairly strong argument can be made that Gatiss and Moffat were adapting the Hammer Horror films of the 50s, 60s and 70s rather than the Stoker novel. Harker’s fate, the awesomeness of Van Helsing, the emphasis on seduction as a vampiric technique rather than the violent assault Dracula uses in the novel, these all come from the films, not the novel.
Visual Effects of Awesome: Props to the makeup department for making Lucy's completely burnt body in Episode 3 both amazing and horrifying to behold.
