- Complete Monster: The Joker opens up the film by brutally beating the young Jason Todd, the second Robin, to a bloody pulp with a crowbar, before leaving him to die in an explosion he sets off. After Joker is released by a reluctant Black Mask from Arkham Asylum to kill Red Hood, Joker demonstrates his random violence by slitting the throat of one of his guards and shooting the other four dead, and soon after backstabs Black Mask by gagging him and the members of both his and Red Hood's gang, intending to burn them all alive for the purpose of getting Red Hood's attention. Once it's revealed Red Hood is in fact a resurrected Jason Todd and Batman turns the tides against Red Hood in the final confrontation, Joker tries to pin Batman down for the purpose of dying with both his arch-rival and Red Hood in an exploding building, absolutely ecstatic that he gets to die getting everything he wants.
- Crosses the Line Twice: The Joker's reaction to finding out that Jason Todd was behind it all is to ask for a picture of the pair "with the crowbar".
- Ensemble Dark Horse:
- Nightwing as depicted here is a Deadpan Snarker played by Neil Patrick Harris, and his comparatively diminished role hasn't made the fans love him any less.
- The Fearsome Hand of Four, despite their limited screen time, are also quite popular as a group of badass cyborg ninja.
- Ms. Li is also quite popular for being a Comically Serious foil to the Laughably Evil Large Ham Black Mask.
- Foe Yay: The Joker interrupting Batman's Tear Jerker speech by saying "aw, so you do think about me!" In the Joker's typically disturbing fashion, he says this while Batman is saying that not a day goes by where he doesn't think about killing the Joker.
- He Really Can Act:
- It Was His Sled: A resurrected Jason Todd, the second Robin, is the Red Hood. For comic book fans, this is common knowledge and the film barely tries to treat it as a genuine mystery for long.
- Jerkass Woobie: Jason Todd/Robin II/Red Hood. He may be a murderer who straddles the line of Anti-Hero and Anti-Villain, but damn if you don't feel sorry for him and even understand some of what he does.
- Ra's al Ghul. Despite his being a ruthless supervillain who, as Batman says, has never shied away from shedding blood, his deep remorse and sorrow over Jason's fate, resurrection, and subsequent rampage are clearly heartfelt and genuine.
- Magnificent Bastard: Jason Todd, after his death at the hands of The Joker and his revival, becomes a much darker figure. Becoming the Red Hood, Jason sets about on his revenge, manipulating Batman, Gotham's criminal enterprises and even the League of Assassins to engineer conflicts to bring him close to the Joker and Batman. Confronting his former mentor, Jason reveals his deep bitterness at the Joker's survival, declaring he believed he would be the last person Batman ever let the Joker hurt. With a manipulative genius to rival even Batman and a hunger to see his own brutal justice enacted, Jason shows he is more than a match for the world's greatest Detective.
- Memetic Mutation: Variations of this piece of dialogue, swapping out Batman, Jason and Joker for other characters/parties:Jason Todd: Bruce, I forgive you for not saving me. But why, why on God's Earth...is he [Joker] still alive?!
- Moral Event Horizon:
- The Joker crosses his in the film's opening scene, as he savagely beats Jason, then leaves him to die.
- Red Hood killing the Joker would not be this. Him handing Batman a pistol and telling him to do it would be, as it boils down to Red Hood wanting Bruce to break his moral code for his sake, when he's had the time and opportunity to kill the Joker himself if he really wanted to. If that doesn't count, he definitely crosses it when he fires at Batman when he tries to walk away.
- One-Scene Wonder: Talia appears only briefly, Evil Is Sexy as always and wielding a Luger.
- Strawman Has a Point: Like in the comic, Red Hood raises a good point on the naivety behind the idea that Batman would not only let the Joker continue to live, but would stop other heroes and villains from killing him, even though the Joker has killed thousands and will kill thousands more in the future. While Batman defends that he does think about killing Joker and doesn't because he's worried about Jumping Off the Slippery Slope, it's willful ignorance on his part — most other members of his Rogues Gallery have temporarily reformed before, or at least there is a real chance they'll reform someday, but the Joker never will and everyone knows it. If there is one time where Batman could break his code, and people in-universe and out would understand why, it's the Joker, and Batman's argument on why he shouldn't are much weaker than Red Hood's arguments on why he should.
- They Wasted a Perfectly Good Plot: Even though Red Hood is revealed to be Jason Todd and thus someone with a very personal connection to the entire Bat-Family, he never interacts with either Nightwing or Alfred despite both being in the movie, and the latter in-particular taking news of Jason's resurrection and fall to villainy almost as badly as Bruce does.
- WTH, Casting Agency?:
- Reactions to John DiMaggio's casting as Joker were... mixed, to say the least. The release of the character models featuring a burlier-than-usual Joker eased concerns somewhat. And then the film was released and a lot of those who doubted he could pull off the role did a complete 180.
- Audiences were also skeptical of Jensen Ackles playing a lead character, as he had never done voice acting work prior to this film. Again, he proved them wrong.
- And anyone other than Kevin Conroy as Batman raises suspicions. But Bruce Greenwood did a good job, especially as a Batman who's supposed to be a little older than we normally see him (though he's one year younger than Kevin Conroy). Greenwood would later reprise the role for Young Justice where he recieved even more praise as a Batman who's decidedly a very good and encouraging mentor.
YMMV / Batman: Under the Red Hood