!!The comics:
* AntiClimaxBoss: Despite years of build up, staying off screen and being the cornerstone by which much of Hellboy's mythology is based, [[spoiler: Satan]] goes down incredibly easily. Of course, it's a JustifiedTrope, because he dies [[spoiler: like [[Theatre/{{Macbeth}} just like King Duncan]], in his sleep.]]
** Despite [[spoiler:his key role in Hellboy's origin, Rasputin also comes across as this to the point that he almost seems to be going through a HumiliationConga from the point he's introduced]].
* [[CantUnhearIt Can't Unhear It]]: Due to playing Hellboy in all other media, Ron Perlman's voice is very easy to imagine while reading his lines. It helps that he was Mignola's [[ApprovalOfGod original choice for the role too]].
* CompleteMonster: In the [[CosmicHorrorStory dark world]] of ''ComicBook/{{Hellboy}}'', Nimue, the [[GodSaveUsFromTheQueen Queen of Blood]], reigns supreme as the greatest monster. Once a mighty sorceress who betrayed the great Wizard Merlin and imprisoned him [[AndIMustScream to live eternally in his own grave]], Nimue was imprisoned for 1,500 years by the witches of Britain. Upon her revival to lead the Wild Hunt, Nimue destroys the other witches of Britain and sets about marshaling an army of the Fae. When one ambassador comes to her to say his king will stand with her, Nimue forces him to murder his king, come out his heart and forge her a new crown with it. Nimue launches vicious purges to ensure there is no threat to her rule, intending to exterminate humanity to the last man. When defeated and being dragged to hell by the witches she'd murdered, Nimue spitefully [[TakingYouWithMe tears out Hellboy's heart to ensure she won't face damnation alone]].
* EnsembleDarkhorse:
** Kate Corrigan was the first, as the team's resident {{Everyman}}.
** Karl Ruprecht Kroenen because of his distinctive design (and the fact that he became an AdaptationalBadass didn't hurt).
** Agents introduced in more recent years, like [[AxCrazy Howards]] and [[BadassNormal Giarocco]], get a lot of fan love.
* HolyShitQuotient: The vision of the apocalypse in ''King of Fear'', not to mention [[spoiler:Hellboy paying back the Baba Yaga... with his *own* eye]].
* SomeAnvilsNeedToBeDropped: You ultimately ''do'' have a choice on what to do with your life, no matter how many times you're told otherwise.
* ValuesDissonance: A given in the Hellboy stories set in the 1950s, a time when racism was widespread in the US, where non-white BPRD agents like Susan Xiang (Chinese-American) and especially Woodrow Fairfield (African-American) are subjected to racist prejudice.
* WhatDoYouMeanItWasntMadeOnDrugs: Read the "Our Angels Are Different" entry.
* TheWoobie: Hellboy and Abe inform the captured Daryl that they will have to keep him imprisoned indefinitely, because killing him will only move the curse. They also tell him that his memories of his family will probably start to slip away, and leave him with a family photograph so he can try to remember.

!!The films:
* SugarWiki/AwesomeMusic: The score for ''The Golden Army'' is very good. Then again it is Creator/DannyElfman, what did you expect?
** Same goes for the first movie. The music playing during the funeral and the end kiss scene alone are great.
** "Mein Hertz Brennt" by Rammstein, used in the trailers, is especially noteworthy. It fits extremely well with the setting and tone.
* BetterOnDVD: The first film had an extended edition, which added on some character development.
* BrokenBase:
** In Spain, Santiago Segura voicing Johann Krauss (which was specially requested by Guillermo del Toro, a close friend of Segura) met a very divided reaction. Some found it surprisingly well done for a non-professional voice actor and very adequate for the character, while others saw it as a disgrace and claimed that other actors would have done the character better.
** The news of the [[ContinuityReboot reboot]]. Some are willing to give it a chance, citing the promising creative team and the implications it may be TruerToTheText than Del Toro's films, given the R-Rating and the announcement that Mignola will be writing the script. Others are less receptive, saying it is unfair to both Del Toro and Perlman, who had long been vocal about their desire to finish the original trilogy. Notably, the majority of the fanbase ''does'' agree that a third Del Toro/Perlman film would have been preferable, the debate is simply whether the promise of the reboot makes up for the former's cancellation.
* DracoInLeatherPants: Prince Nuada, [[WhiteHairBlackHeart naturally enough]] for an expy of [[Literature/TheElricSaga Elric]]. It helps that he does have something of a point, the magical beings ''are'' being forced out.
* EngagingChevrons: Parodied in the first movie, a guy with a high-tech flamethrower backpack goes through a long, drawn-out start-up sequence, only to be eaten by the thing he's trying to kill before he can use it.
* EnsembleDarkhorse: Kroenen, for being an AdaptationalBadass and CreepyAwesome clockwork zombie.
* EvenBetterSequel: Despite diverging even more from the source material, ''The Golden Army'' is liked just as much as, if not more so, than the first film.
* HoYay: It says something about the writers (or maybe the actors) that one of the most romantic scenes in the either of the films is two dudes getting drunk and singing "Can't Smile Without You" to each other.
* InternetBackdraft: Many fans were NOT happy when the third film was cancelled in favour of a reboot and that Mignola was responsible for it. [[RuleOfCautiousEditingJudgment Let's leave it like that]].
* JerkassWoobie: Nuada.
* MagnificentBastard: Nuada again. He's a [[WellIntentionedExtremist genocidal dick]], but you can see where he's coming from.
* MoralEventHorizon: Prince Nuada starts off by unleashing a swarm of ravenous tooth fairies in a room full of people, the tooth fairies ate every last bit of everyone in that room till there was nothing left of them. There is absolutely no purpose to this either, as he already has what he came for. He does it just because they're humans.
* NarmCharm: In the first film when Hellboy's fighting Sammael in the subway, he also has to protect a lady's box of kittens. It's completely ridiculous and contrived, and yet very endearing.
* OneSceneWonder: The Angel of Death in the second film is only on screen for a couple of minutes, but is one of the most memorable. Not only does its distinctive look lead it to be heavily featured in promotional materials, but it very potently reminds everyone, in- and out-of-universe, just what Hellboy is.
* OvershadowedByControversy: Narrowly averted. The reboot initially cast the white British Ed Skrein as Ben Daimio, an American of Japanese descent, and which led to an outcry and accusations of whitewashing, seen as particularly bad in light of [[Film/DoctorStrange2016 multiple]] [[Film/GhostInTheShell2017 recent instances]] [[{{Film/Aloha}} of similar casting]] [[Film/Pan2015 controversies]]. Skrein admitted that he had no idea of Ben's ethnicity and stepped down immediately, leading to Daniel Dae Kim, who was much better received, being cast in the role and preventing the film from being hit with the controversy that damaged the aforementioned films.
* PeripheryDemographic: The first film received a good review from [[http://www.pluggedin.com/videos/2004/Q1/Hellboy.aspx Focus on the Family]], of all people.
* TearJerker:
** The death of [[spoiler:Professor Broom]] in the first film.
** In the second, [[spoiler:Nuala's]] sacrifice, particularly because it makes Abe of all people shed a tear.
* UglyCute: "[[http://www.youtube.com/watch?v=CxVPrrNZntI I'm not a baby]], [[CrowningMomentOfFunny I'm a tumour]]."
** Nuada, if you're not tired of yet another WellIntentionedExtremist ranting against the black and white evil that is humanity.
* VisualEffectsOfAwesome: And relatively small budgets.

!!The animated films:
[[YMMV/HellboyAnimated See here]].

!!The video games:
* TheProblemWithLicensedGames: Both Hellboy games had outdated graphics and repetitive gameplay, and the first one was full of bugs. Although ''The Science of Evil'' was supervised by Mignola and Del Toro, it didn't make up for the programming shortcomings.