- Ensemble Darkhorse: Ben Foster's character, "The Stranger".
- Faux Action Girl: Amber in the sequel. She exists mainly to complain about how Stella is useless in a fight and is going to get the rest of the group of vampire hunters killed. She kills exactly zero vampires, gets Todd killed when she panics in the middle of their first operation as a group, dies herself during the climax, and provides nothing in the interim except needless antagonism towards the female lead.
- Sequelitis: The first 30 Days is noteworthy for its departure from so many worn-out vampire cliches, even borrowing a few details from zombie stories back before it was fashionable to do so. Dark Days, by contrast, is as paint-by-numbers as you get, replacing tense survival horror with generic guns-blazing action and reintroducing several of those vampire cliches in the forms of Dane, a Friendly Neighborhood Vampire who works with the vampire hunters and feeds on blood packs; and Lilith, an Evil is Sexy blood-bathing Vampire Monarch (named Lilith) whose design hits much closer to Cute Monster Girl than even other female vampires. She even has a human pet! That doesn't stay human. The kicker to this? The script is co-written by one of the creators to the comics.
- Special Effects Failure: The CGI "blizzard" is Syfy-standard, as is the killing of the head vampire and Eben's death.
The Graphic Novel
- Awesome Art: Ben Templesmith's unique and gritty style in the first three arcs of the series, as well as Red Snow.
- Hilarious in Hindsight: Three Tales has an issue entitled Dead Space. Ben Templesmith — the artist for 30 Days of Night, Dark Days Return to Barrow, and Red Snow — ended up doing the artwork for some of the Dead Space comics.
The Novel Spinoffs
- Complete Monster:
- Bork Dela, introduced in Immortal Remains, is a vicious, vampiric Serial Killer dubbed "the Headsman", who goes on a killing spree in Savannah, Georgia. He kills men and women alike—often in their own homes—leaving behind very little if any blood behind in the process, and always beheading his victims. While investigating the series of murders, Dane discovers a woman whom Dela had raped. It's revealed that prior to his turning, Dela was said to have been the one who introduced Hitler to the occult, and may have had a hand in his death. He had also been Vicente's bodyguard before Eben killed him. When Dane confronts him, he calls Dela out for his Fantastic Racism, and Dela retorts that Dane's sympathies for humans are like celebrating having once been apes. Later in the book, it's revealed that he has been supplying the rogue vampire Elder Enok, with blood. Ax-Crazy and bloodthirsty even by vampire standards, he cares nothing for the Masquerade enforced by the Elders, and his evil deeds cannot be even remotely justified by Transhuman Treachery or a need to survive.
- Introduced towards the end of the same book, the aforementioned Enok is a dreaded rogue Elder who turned both Vicente and Lilith—whom is shown to be still very-much "alive", yet dismembered and incapacitated, and in Enok's captivity—thus being somewhat responsible for both the destruction of Barrow and the slaughter in Los Angeles, respectively. He dwells in a human slaughterhouse where people are rounded up, shot in the head, and their blood is drained into buckets to be fed upon like free samples, and plans to overthrow humans as the dominant species and reduce them to cattle, presumably to be farmed for their blood and slain in slaughterhouses like this across the globe. When Dane and Eben confront him, he sentences Dane, whom he considers a Category Traitor, to be killed by a horde of ravenous vampires while he tries to fight Eben—a Worthy Opponent in his eyes, to contrast with Dane—into submission, or kill him if he refuses. Malevolent and horrifically ambitious, Enok is by far—at least prior to Eben's Face–Heel Turn in the comic—the most terrible vampire in the series, Elder or not.