* AlternativeCharacterInterpretation: There's a large camp of people who believe Dr. Horrible and Billy are two separate people in one body, as evidenced by some of the trope comments below, even though [[{{Fanon}} this was never revealed in the show]].
** Also, whether it's a multiple personality or not, is Billy a genuine shy nice guy, or a passive-aggressive Nice Guy (TM) who, while less openly selfish in his pursuits of relationships than Captain Hammer, is not really any more interested in her as a person? It's a good story either way, but a very different story.
** Is Billy really [[LoveAtFirstSight in love with Penny]], or just InLoveWithLove?
** Penny, on one hand, she dates a guy who's not very subtle about what a giant JerkAss he is because he's famous and can help her with her personal goals, she's possibly emotionally cheating on said JerkAss with Billy, and she quite possibly uses [[spoiler: her last words]] just to twist the knife in someone's gut. The view of her as being full of IncorruptiblePurePureness is more Billy's projection, and looking at what she actually does shows her as flawed and shallow like everyone else in the story.
** Then on the other hand, should she really be able to see Hammer's jerkiness? He's fairly low-key around her, until the press conference, where she sees it and doesn't like it a bit. Is she just using Hammer to achieve her own personal goal? Since her goal is a to help the homeless, is the manipulation unjustified?
* SugarWiki/AwesomeMusic: Difficult to pick.
** Predictable, as it's a chock-full-of-SugarWiki/MomentOfAwesome ''musical''!
* DracoInLeatherPants: The {{Fangirl}}s/[[{{Fanboy}} boy]] give this treatment to both Captain Hammer and Dr. Horrible.
* EarWorm: The songs are -- dare we say -- ''horribly'' catchy.
* EnsembleDarkhorse: A literal case here with the Thoroughbred of Sin himself, Bad Horse; despite only featuring in two short songs and having a brief physical cameo at the end, just about everyone loves Bad Horse.
** He's a ''[[EvilGenius supervillain]] [[TheMafia Godfather]] [[AnimalSuperheroes horse]]'' who delivers orders via ''[[MundaneMadeAwesome cowboy-themed musical telegram]]'', and has the amazing ability to sign phone calls.
** Despite only appearing in a contest entry video, Tur-Mohel quickly became a standout.
* EvilIsSexy: The aforementioned "Slipping." [[EarWorm Irrepressibly catchy tune?]] Check. Haunting melody? Check. A voice that brings to mind a master of seduction? ''Check to the eight-millionth power''.
** On the commentary, Maurissa Tancharoen says, "This is ''my'' favorite scene" when NPH grabs her chin.
** "Brand New Day." PsychoticSmirk. That is the very definition.
** Captain Hammer's groupies switch to worshiping Dr. Horrible in the end, although there's a healthy component of fear there too.
* FashionVictimVillain: Apparently, silly costumes are a requirement for the Evil League of Evil.
* FauxSymbolism: Dr. Horrible's overlarge armchair in which he plots world domination. Either he feels inadequate or it's just for comedic effect.
** See the {{Jossed}} entry in Trivia--that chair just happened to be in the house where they were filming.
* FridgeLogic: When Billy spies on Penny, at one point he sees her eating frozen yogurt.
* FoeYay: Between Captain Hammer and Dr. Horrible, who seem to take their relationship very seriously:
** Dr. Horrible mentions at the very beginning of his blog that Captain Hammer is his nemesis, not some poser in a parka. Captain Hammer apparently returns the feeling as he admits in his song that everyone's villains aren't as cool as his.
** "These... Are not the hammer. The hammer is my penis." One act later, Dr. Horrible taunts him with "Hammer, meet nail!" If that's not a {{Metaphorgotten}}, it's a very revealing FreudianSlip.
* HarsherInHindsight: The fan reaction to Loki in Whedon's film of ''Film/TheAvengers'' is eerily similar to how the public react to Dr Horrible in the ending, especially considering that they had the same motives (taking over the world in an effort to make it a better place) - Loki kills hundreds of people, but he's still worshipped as a villain, just like Dr Horrible was, complete with obsessed fangirls.
* HilariousInHindsight: The line "Let's all be our best" from "So They Say" is now quite reminiscent of [[{{Dollhouse}} another Whedon work.]]
* HypeBacklash: Can a modest 45-minute humorous short really live up to the massive praise heaped upon it by its fans? [[CaptainObvious Some say yes.]]
* InternetBackdraft: Whatever you do, don't start a discussion on whether Penny's fate was a standard-issue StuffedIntoTheFridge death, or a deconstruction of said concept.
* MagnificentBastard: Doctor Horrible evolves into this as the story progresses.
* MemeticMutation: "The Hammer is my penis."
** "ShinyNewAustralia".
* MisaimedFandom: Some people, as highlighted in [[http://karjack.livejournal.com/656327.html?format=light this essay]], are arguing that a large part of the audience seems to have missed the point especially in the way it tackled the idea of WomenInRefrigerators and of Billy as a [[DoggedNiceGuy Nice Guy]]. Billy's complete transformation into the Dr. Horrible persona is clearly and unambiguously portrayed as a tragedy; not only because of the loss of Penny, but because it costs him the very humanity that his friend associates with. Some people are still going to prefer the WellIntentionedExtremist Dr. Horrible over the nebbish StalkerWithACrush Billy.
** More worryingly, some Youtube comments imply that a few people wish they could deal with their bullies the way that Billy goes on to do. This is slightly worrying, to say the least.
* MoralEventHorizon: Captain Hammer dating and sleeping with Penny ''just'' because he knows it'll hurt Billy[=/=]Dr. Horrible. He might be a superhero, but this moment makes it clear he's not in it because he's a good person. This is ultimately what causes Billy to plot to kill him- not the countless times Hammer's foiled his crimes and beaten him up.
* PuritySue: Penny. She is goodness taken UpToEleven. She's optimistic, active in lending support to the homeless, and is all-around cheerful. Plus, she attracts the attentions of both Billy and Captain Hammer. [[TooGoodForThisSinfulEarth And she's doomed, because Joss Whedon doesn't know any other way to handle a plot.]]
* TearJerker: (Dr. Horrible) [singing in Act III] "And I am fine." (The look on his face and the camera's pull-away show he's anything but. He's hurting and alone.) and [singing at the end of Act III] "''And I won't feel''..." [the door slams shut] - (Billy) "...a thing."
** "Still Alive"...
** "It's okay...Captain Hammer will save us."
* TheWoobie: Not only does Dr. Horrible get roughed up on a regular basis but takes it in stride ("...honestly, I'll live."), he suffers the emotional equivalent of a punch to the gut several times. "Penny's Song" establishes Penny as this to some extent, although she's far too optimistic to let it stick.
** IronWoobie: He's taken a ridiculous amount of abuse, and he doesn't remotely look like it. Hammer threw a ''car'' at his friggin' ''head''!
** JerkassWoobie: But at the same time, Dr. Horrible is a CardCarryingVillain.
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