Throughout the entire movie, the enemies that give Batman the most trouble are dogs. Are we talking about actual dogs, or the Joker, whom is referred to as a "mad dog"?
The two heist henchmen not let in on the "Kill Our Partners" ploy were Dopey and The Bus Driver (name never given)... the first to be killed, and the one The Joker planned to kill himself.
Grumpy confronts Bozo (The Joker) about the doublecross right when his own job was finished and thus the exact moment he surmised Bozo would assassinate him.
The Bank Manager's tactics were actually pretty sound. Out of the three heisters (that he knew about), only one was holding a submachine gun (Chuckles had a MAC-10). The other two were holding pistols (even though Bozo's was a full automatic pistol). Once he took Chuckles out, he had the others outgunned (his shotgun was far more lethal at close quarters than any pistol could be).
Dent's coin, which is in fact a Two-Headed Coin: He flips it several times, as if to make a decision based on the outcome (at one point conning Rachel into agreeing to go out with him if it comes up Heads). The coin always comes up heads because Harvey Dent always does the right thing. Tails isn't an option. It's only when he becomes Two-Face, and one side of the coin is defaced that any other outcome becomes possible for him.
A lot of critics referred to the film bordering on tragedy; the structure of the film makes a little more sense if you keep in mind the traditional five-act arc of Shakespearean dramas, in which the climax comes earlier than a traditional three-act arc and ends on a lengthy, melancholy resolution (in this case, Dent holding Gordon's family hostage).
Also, Dent's coin flips alternate perfectly — if it comes up bad, the next will come up good, and so on; this may be why he also flips on Maroni's driver after the coin spares Maroni. But When Batman tackles him, the coin comes up good for the second time in a row; ultimately, it's not Dent who makes his own luck, but Batman who intervenes to ensure that Dent's victim is spared and Dent's own "good" face is the one that will come up in the aftermath of his death.
During the scene where Batman interrogates Joker, Joker cautions him that striking the head first makes the victim fuzzy. Minutes (and several head-slams) later, he gives Batman the correct addresses, but mixes up the hostages. Though the Joker gave him a Sadistic Choice and intentionally mixed up the addresses, it could almost be Black Comedy. He did warn Batman that the victim's head gets fuzzy...
Bearing in mind that the Joker does things like this adds an extra twist to the scene with the two barges. What would have really happened if someone had pushed their detonator? Were they wired to their own barges, to another building, or was the one in Joker's hands the only working one? This makes the Prisoner's Dilemma even more complicated if the occupants of both boats think that their detonator won't blow up the other boat.
During really tense moments (such as when Batman is interrogating Joker), the soundtrack takes on a high pitched tone, automatically making the viewer nervous.
In the climax, Batman tells Harvey that Joker chose him because "he wanted to prove that even someone as good as you could fall". So, in other words, Joker wanted to bring one of Gotham's best people down to his level. Sound familiar? The only difference is that this time, The Bad Guy Wins.
That's not all. By doing so, Joker indirectly made good on his promise of forcing Batman to break his one rule.
In the climax, Harvey is determined to avenge Rachels death by any means necessary, even if it means torturing Gordon by killing James Jr to do it. However, before he moves on to James Jr., he flips the coin for himself and looks disappointed when it comes up clean. Why would he flip the coin for himself if it meant there was a chance that he would die before his mission is actually complete? Because Harvey still believes himself to mostly be a force for good, even if he is extreme, and he genuinely doesnt want to kill the boy, he only feels as though he has to for his mission. This both explains the weird coin flip order and why he doesnt actually point the gun at the child (aside from the real world explanation of avoiding an R rating). The reason for the disappointment? The fact that he survived means that James Jr. is next, and he HAS to flip the coin. His life is now out of his hands.
"Five dead, two of them cops". These numbers don't make sense at first, since we only see Harvey kill two people for certain. However, with a little thinking, the numbers do make sense.
Three of them are already accounted for: Wuertz, Maroni's driver, and Harvey himself. Wuertz is also one of the cops.
There is next to no way that Maroni survived the car crash. He's already wounded and not wearing a seat belt, whereas Harvey himself is already a walking Determinator who refuses to stop despite his injuries and is shown putting his seat belt on. Between the car flipping and the way it crashed, Maroni died in the crash.
The last victim is one that Harvey himself didn't kill: the cop who came in to get him out of the hospital, the same one The Joker kills while he's still dressed as the nurse. This cop was last seen going in to get Harvey out, and with Gordon unaware that the Joker was inside the hospital just before he blew it up, Gordon would instead put the kill on Harvey's count since he now has no reason to believe otherwise (for all he knows, Harvey simply killed the cop on his way out). Thus, "five dead, two of them cops".
Joker's Game of Chicken with the Batpod basically sums up why he's such an effective supervillain in one scene. Batman relies on fear and intimidation to beat criminals. But the Joker is something he's never faced before. The Joker is someone who's not afraid of him. While any other criminal would get scared and run, Joker just takes a gun and screams at Batman to hit him. Either because he knows full well that Batman won't actually do it, or (judging by his reaction after Batman didn't do it) because he actually wants him to. Probably both.
In the Alternate Reality Game that ran before The Dark Knight there was a website called ccfabg.org (Concerned Citizens for a Better Gotham) run by corrupt cops and their mob connections, which was trying to smear Harvey Dent. If you sent in your email to the organization, you would get swag back from the organization as is customary for Alternate Reality Games. One of the items was a pin button with a picture of Harvey on it, one side clear and the other side red and scaly. What seemed like a Mythology Gag at the time actually has a valid explanation In-Universe. As explained by Gordon, Harvey's nickname was "Two-Face", so it would be a little inside joke for the corrupt cops to send out a pin like that.
The Joker's Multiple-Choice Past isn't just a nod to The Killing Joke, it lampshades the Joker's motivation as a Whole Plot Reference to the comic. Each of his backstories strongly implies he went mad due to having one bad day, and in the comic, the Joker outright states he feels that such a day would drive anyone to insanity. This is his motivation in the film, testing both Harvey Dent and Batman along such lines, but in the climax he pushes all of Gotham to this.
In this version of the Batman story, the Joker starts out as a Psycho for Hire for the Gotham Mob who eventually grows beyond their control, contrasting most other versions that present him as an A-List player in the Gotham Underworld who has more-or-less always acted alone. While that might just seem like an easy way of connecting the Joker to the Carmine Falcone story arc in the first movie, it also greatly aids the movie's real world subtext by inviting comparisons to several historical "monsters" who started the same way. Adolf Hitler, for example, was originally just an angry firebrand who had no real power until Anton Drexler invited him to join the German Workers' Party, believing that his oratory skills could finally earn them some real recognition; Osama bin Laden got his start when the CIA gave his allies weapons and military training, believing that they and the Mujahideen could be useful in driving the Soviets out of Afghanistan; and many, many of the 20th century's worst dictators rose to power as a result of the Cold War, when either the Soviet Union or the United States saw them as potentially friendly to their interests. In Real Life, truly evil people very seldom rise to power alone. More often, they only get there when already-powerful people try to use them as pawns in their larger struggles.
It's easy to view Coleman Reese's swift willingness to back down from his scheme as simply because Lucius Fox points out that the man he's planning to blackmail is both a powerful billionaire and a potentially unstable and violent vigilante. But there's a third reason. Fox specifically makes a point of noting that Batman beats up not just anyone, but "criminals". Reese is planning to blackmail Bruce Wayne. Blackmail is a crime. The Batman would thus come after Coleman Reese not just out of spite, or vengeance, or fear for his secret, or insanity, but because Coleman Reese was a criminal... and thus a valid target for the Batman. No wonder he's so quick to not just give up on his scheme, but also give up the only evidence which would prove he was attempting to commit a crime.
There's also the fact that Fox starts his Let Me Get This Straight... speech by noting Bruce is "one of the richest, most powerful men in the world," before noting that he "spends his nights beating criminals to a pulp with his bare hands." Coleman is screwed from either (or both) of two directions: Bruce Wayne can use money, power, and influence, or Batman can pummel him with his fists. Either way, Reese is tangling with a man who can destroy him with ease.
When Alfred talks about how "some men just want to watch the world burn", he mentions how during his mercenary days his Eureka Moment came when the day he "saw a child playing with a ruby the size of a tangerine." This is a direct reference to The Man Who Would Be King, specifically these◊ rubies.
Joker has a whole speech about how nobody panics when everything goes to plan, and will act shocked when it doesn't. A few minutes later, he stops in his tracks when the bombs stop going off in the middle of his Unflinching Walk, only to scamper off when they start up again. He just proved his own point by complete accident!
During the climax in the under construction office building where the SWAT team moves on the hostages, the boys at Rifftrax note that not once does the Gotham SWAT actually open fire. Of course, given the situation it makes sense. The rooms are filled with hostages, and a single stray round can kill a hostage. They know the Joker has something planned, and if they fire at all it might play into what he wants. Finally, for them Batman has been helping to clean up Gotham and helping them while never once going after the good cops. Even knowing that Batman is interfering with their given mission, they can't bring themselves to fire on him.
During the Batman/Joker discussion in the cell. At one point, the Joker says/quotes the Jerry Maguire line "You... complete me!" At first it just sounds like a throwaway line for a cheap laugh until you consider the source: in the movie, Jerry Maguire, until the scene that line comes from, almost always gets around with a rictus grin on his face - Does This Remind You of Anything?? Also, Jerry Maguire's meant to be seen as an antihero - again, probably how the Joker sees himself.
Two pieces of Alfred's dialogue within Batman Begins and The Dark Knight are very similar. The first happens just after Bruce's parents die in Begins, and the second after Rachel dies in Dark Knight.
Alfred: I thought I'd prepare a little supper... (Bruce looks out his window, silent). Very well, then. Alfred: I thought I'd prepare a little breakfast... Very well, then.
In the opening, Joker hides among the bank robbers working for him. During the car chase scene, Gordon hides among the cops. There's a recurring theme of hiding things, all though the movie.
Not just hiding, but hiding in plain sight. Both those examples, as well as Joker hiding among the cops during the assassination attempt, are all hiding in plain sight.
And in Begins both Ducard and Batman made a tactic out of hiding amongst identically dressed ninjas during Batman's initiation into the League of Shadows.
It's even present in the first shot of the film. Remember the film starts with the Joker having his clown mask off. He doesn't remove it at any point to put his makeup on during the opening sequence, with the conclusion being he had it on the entire time he was just standing there in the middle of the street, quite openly, for everyone to see his face. He is hiding right there in plain sight.
Batman reverses this trend. Even his enemies can tell him apart from numerous vigilante copycats—because for Batman, the cowl isn't a disguise.
The Joker says he doesn't make plans, but this obviously isn't true. Because he's lying. He's a consummate liar, remember? He says whatever would twist the knife more. For someone like Harvey, who has dedicated his life to Lawful Good, saying he's Chaotic Neutral is an excellent way to hurt him.
The Joker and Bruce at the party:
Many remember the scene of the Joker crashing Bruce's party, entering with: "Where. Is. Harvey. Dent?". However, shortly before that scene, where Bruce himself joins the party he asks "Where is Harvey-" and cuts off as he sees him, implying he may have been about to say Dent. Coincidence, or an attempt to draw parallels between Batman and Joker? Probably the former.
Both of them show up late, make big dramatic entrances, surrounded by a group of people, and immediately ask where Harvey is. It's entirely to subtly show parallels, and the contrasts; both of them are costumed people, Batman works outside of the police to help them deal with an enemy who has them on the ropes, using theatricality and manipulating emotions to win, and the Joker does the exact same thing for the mob. In both cases each of them sees Harvey Dent as the person that will carry on their mission.
When Two-Face grills Wuertz about what the mob did to him and Rachel, Wuertz responds with "I didn't know what they were gonna do to you!" Harvey then spins his coin and says "Funny, because I don't know what's gonna happen to you." It seems like a better line would be "Funny, because I don't know what I'M gonna do to you." But when Two-Face uses the coin, he abdicates responsibility for his actions, so Harvey would never use that line. To Harvey, the coin killed Wuertz.
Remember the dinner scene between Harvey, Bruce, Rachel, and Bruce's Russian ballerina date? How the ballerina holds a piece of white paper over Harvey Dent's eyes, suggesting he could be Batman. The point being: Harvey is Gotham's white knight, with a white mask, at that point, while Batman's is unremittingly dark.
Also, remember Dent's speech before he 'reveals' himself to be the Batman, where he says, "The night is always darkest just before the dawn." 'The Dark Knight' can also be interpreted as 'The Dark Night', the dark night being the reign of terror on Gotham being perpetrated by the Joker.
The bank manager played by William Fichtner tell the Joker that "The criminals in this town used to believe in things: honor, dignity...". As a manager of a mob bank, he was working for some high-ranked criminals and probably came up with the whole "honor and dignity" thing to justify his actions to his own consciousness. Organized crime generally tends to have their own code of honor, preferring to think of themselves as businessmen rather than criminals. The higher in the mob you go, the more detached from the down-and-dirty acts of crime you become, and the more you can hold yourself to loftier ideals. Plus, this was said in the context of him witnessing a ludicrously extreme case of backstabbing that it's very easy to believe even the mob would hold themselves above.
Joker molding Batman:
The Joker was very skillfully manipulating Batman into the person that the Joker wanted him to be. Thinking over the hostage bit, when Gordon and the police were on their way to save Dent, or so they thought, both Gordon and Batman believed the Joker when he told them where he was holding Harvey and Rachel. This had two possible outcomes, with Batman in the position of making a Sadistic Choice either way. If the locations hadn't been switched, and Batman successfully saved Rachel, that would leave Gotham without its White Knight, which would pave the way for a new era of crime and corruption in the city - just what the Joker promised the mob guys earlier in the film. However, the second way, as had occurred in the movie, was also immensely profitable to the Joker. With Rachel dead, there's nothing standing in the way of Batman devoting himself to fighting crime, and the Joker would have his opponent. Not to mention, he STILL takes down the White Knight side of Dent by exploiting his bitterness at surviving. Either way, the Joker wins.
It runs a little deeper than that. The Joker has effectively and affectively put Batman in the same position he gave the two boats, he simply hasn't informed him of it ahead of time. Either he condemns the DA to death in order to save the girl, then has to face the D.A. knowing that he was ready to throw away his life for personal gain, or he condemns the woman he loves to die in order to save the D.A., only to have to face her knowing he made that choice. No matter what happens, everyone loses; Batman gets to live with knowing that whichever one survives, he consciously made the choice to let them die. Likewise, the survivor gets to live knowing that Batman allowed their lover to die. Honestly, whichever gets blown up was probably the most merciful outcome of the three.
Imagine what would have happened if Batman didn't swerve at the last minute and just plain killed the Joker outright. The plan to take Harvey and Rachel was obviously already in effect before the chase. If the Joker had died, the police would have had nobody to tell them the whereabouts of Harvey or Rachel in time to save either of them, then and both would be dead, and you guessed it, Batman would have been at fault and would have had to live with the guilt of what betraying his principles led to for the rest of his life.
Which sounds an awful lot like it could be Batman's "One Bad Day." Maybe the Joker really knew what he was saying when said "Come on, hit me, I want you to do it!"
The Joker's declaration that "I think you and I are destined to do this forever". He's not talking about a rematch! He no longer cares if he gets imprisoned forever or even executed for his crimes. He already won when Batman failed to rescue the woman he loved. The Joker knows that Batman is the sort of person who would obsess over every mistake he made, wondering if he could have done something different and saved her. That's why they two of them will be battling forever; he'd be replaying the entire time battling against the Joker.
Why didn't Joker tell Harvey a scar story? Because he would've already heard one from the people at the party, especially Rachel. He does, however, tell him a different lie; that he's entirely Chaotic evil without any real plans whatsoever. For someone like Harvey, who has lived his life by The Plan, the idea that one lunatic could do so much damage hits him right in the soft spots.
Batman taking the charge for Dent's killings gave Dent 2 "faces": one is the face of a hero, as viewed by the city, and the other of a villain, as viewed by Batman and Gordon. Harvey had truly become a "two-faced" person, not just a nickname.
For the first half of Dent's vigilante spree, the coin seems fair and balanced. Let's look at the verdicts and whatever evidence may be present:
The Joker: Implied to be guilty, but considering how Dent was holding his gun, he wouldn't have been able to kill the Joker anyway except under two conditions. He's the one that rigged the warehouses, and he's the one who knew where both Harvey and Rachel were being held, so he was probably the one who gave Dent's warehouse to Wuertz and Rachel's warehouse to Maroni's driver. And yet, he considers what happened to both of them to be just business.
Detective Wuertz: Guilty as charged. The guy's statements to him at the bar are contradictory: first, he mentions that he thought Dent was dead, and then that he didn't know what the Joker's goons were going to do to Dent. This makes it clear enough that he willfully assisted the Joker in trying to murder Dent. Plus, he refused to rat the other corrupt cop on Gordon's force.
Sal Maroni: Not guilty. It's hinted that he never really wanted to hire the Joker in the first place, and when Rachel is killed his doubts are confirmed; right before the Joker attacks the hospital, he rats the clown to Gordon, something he earlier wouldn't do even at the urging of the Batman (mainly because at the time, he was too scared of a vicious and violent reprisal against the Falcone crime family). Whether he survived afterwards, though, is up for debate, because the verdict for...
Maroni's driver: Guilty. It's hinted that he's one of two drivers that take Rachel and Dent to the warehouses to face imminent incineration unless Batman and Gordon picked them up before the warehouses went up in smoke. And yes, it's entirely possible that he was completely willing to assist the Joker, unlike Maroni.
Detective Ramirez: Not guilty. Her statements when confronted by Dent indicated that she was coerced into handing Rachel over to the Joker's goons and that she didn't want either her mother or Rachel to perish.
That said, only when Dent kidnaps Gordon's family does it become completely obvious just how twisted he's become due to the Joker's machinations; Batman is judged guilty and tagged, and Dent is judged not guilty. However, after Batman tackles Dent to try to subdue him but winds up inadvertently killing him instead, it's revealed that James Jr. got judged not guilty, just for symbolism's sake.
Ah. . . but would the coin have landed "heads" up if it had been caught in Harvey's hand instead of falling an extra few feet to the floor?
Several of the Joker's origin stories as presented in other media portray his creation as the end result of him being poisoned. Maybe the truth of the matter is that he got hit by the fear toxin (a concentrated dose, even!) during the climax of Begins and went from a mild-mannered actor to a batshit crazy psychopath in one night...
Some people have pointed out that it is strange that the Joker seemingly gets offended when people call him a freak but he has no problem calling himself and Batman freaks. The Joker isn't offended by the word 'freak,' but HOW it is used; the mob calls him a freak like it is a bad thing. He knows he is a freak and Batman is a freak but sees both of them as the next step, above the people. They are freaks because they are better than normal. Being a freak isn't bad... it is the only way to survive.
The Joker's goal throughout this film is to spread anarchy and chaos. During the ferry scene, the ordinary citizens decide to vote on whether they detonate or not. Then it was decided on a vote 396 out of 536 that they should (which is a 74% majority), but they still don't do it. Voting is a democratic process. So as a whole, they democratically voted to blow up the ship. But they decide not to do it anyway. Everyone turns their back on the decision the group made as a whole, and that, by extension, is anarchy. Even so, that they decided not to do it anyway (in unison, at that!) proves that the Joker only succeeded at half (there's that word again) of his goal, because though it was an act of anarchy, no chaos occurred in the process.
In the hospital scene with Dent and Gordon, Dent at one point says, "Why should I hide who I am?" Fridge Brilliance: As he turns around to say that, the camera effectively hides what he has become a mere second before showing his Nightmare Face. Irony and Visual Pun combine gloriously here.
The defining word for this movie has to be half. Let's look at the examples, whether invoked, Brilliance, or metaphorical:
The Joker wants to expose the other half of people for them to do bad.
Joker wants half of the mob's money.
Half of Harvey's two-headed coin is burned.
Half of Harvey's face is burned.
Joker burns half of the mob money.
By the end, Batman has corrupted half of his image; adults despise and/or fear him, but he is adored by children, who hope for his eventual return.
The only burning my half Brilliance in regards to Harvey's condition.
The poster for The Dark Knight shrinks Batman down to half the image.
For the first half of Dent's vigilante spree, the coin seems fair and balanced.
The Brilliance of the Joker only succeeding at half of his goal with the civilian boat: Anarchy, but not chaos.
Natasha covers half of Harvey's face with a white piece of paper when thinking that he could be Batman.
Gordon's son gets the same chance Rachel had. Fifty-fifty, or half. This extends to Joker, Wuertz, Maroni, his driver, Ramirez, Batman, and Dent himself.
Dent tells Wuertz that he's half dead.
The League Of Shadows could have funded the Joker to destroy Gotham, and this can be valid for several reasons. One, because the personification of Ra's Al Ghul varies widely from version to version. For this Brilliance, I'm fastforwarding to one movie that involved Joker and Ra's on a large scale. In UTRD, Ra's is perfectly willing to hire the Joker as a distraction for Batman, but he underestimates his control over him when he kills Jason Todd. This Ra's is saddened to the death of him, and becomes The Atoner. Now, go back to this film and look at Joker's actions. Multiple-Choice Past? Something someone working for a secret mastermind would do. Chaos? What Ra's wanted in the first film. Destruction? His ultimate goal for Gotham. Like Ra's, the Mob underestimated their control over him, and he let loose in the wham scene across each film. Something Ra's isn't afraid of, because he brings chaos and destruction, which will only go higher with the Joker's escalating acts of terrorism. The League might not be present in person, but in a metaphorical way, in a madman no one would see coming.
Harvey and the Joker's speech:
Of course Harvey falls for the Joker's speech about how he didn't mastermind the Rachel and Harvey bomb setup. Harvey is a prosecutor who goes after organized crime. And the guys out on the street, doing the grunt work in organized crime, aren't in any position to make decisions, they aren't the masterminds. So when Joker users some Weasel Words, starts talking up the "schemers", and saying that for the Joker, it was Nothing Personal, that fits right in line with Harvey's already established mode of thinking. He automatically reverts to thinking of the Joker as being in the same role as a gang enforcer: just someone doing the bidding of a superior. "The Joker's just a mad dog, I want the one who let him off the leash."
This also fits in with other themes the movie has run with before including that people don't really understand the Joker, because his worldview is too alien to them, (how well can someone who does want something logical like order, money, and control understand the man who just wants to watch the world burn) and Joker exploits that misunderstanding and underestimation to his benefit. Because Harvey will believe his lies, Joker can turn Harvey into the Fallen Hero and crazed psychopath, just like Batman consistently is one step behind the Joker, or the SWAT team can be tricked into targeting innocent doctors instead of the thugs they're after. The Joker's greatest weapon is being an Outside-Context Problem, and being able to hide just how far outside of context he is to fool people who wouldn't imagine what he's really like and really up to.
The novelization provides one of the most powerful quotes to describe Joker's methods of corruption compared to the movie. It's especially poignant when considering Two-Face.
Film Joker: I'm only burning my half. Novelization Joker: I'm only burning my half. Of course, your half will burn with it. Nothing to be done, I'm afraid.
Joker: "It's not about the money; it's about sending a message." Two-Face: "It's not about what I want! It's about what's fair!" What does it mean? I'm not sure. It's not an indication of Two-Face drawing influence from the Joker, since the former was not present when the latter said his line. It could be Nolan's why of making clear that neither of these villains are pursuing the normal, often cliched motivations. It could be a nice contrast between the two, while still highlighting their similarities. It's up for grabs. The lines provide a contrast between the two; the Joker wants to serve only himself, whereas Two-Face wants to serve only cold-blooded justice according to coin flips. The Joker throws away money in favor of his own interests, whereas Two-Face throws away his own interests in favor of justice.
Every other incarnation of the Joker is, first and foremost, a killer prankster. As deadly as they are, most of his traps and crimes are set up as jokes and gags. Heath Ledger's Joker dispenses with the pranks in favor of being as terrifyingly effective as possible using the simplest of methods. He hides bombs rather than gift-wrapping them for someone to find. He prefers knives over guns because mutilating someone with a knife is more personal and terrifying than simply shooting them with a gun... although he's not averse to shooting if it's more efficient. Every gun he handles in the film is a real, working weapon that fires actual bullets—no "BANG!" flags here. He's a practical Joker, you see.
The Joker's lip-licking Character Tic is due to Heath Ledger being annoyed by the prosthetic makeup and unconsciously licking at it and it being worked into the movie, but just as people can't seem to help picking scabs or tonguing a missing tooth or other mouth injury, the idea of the Joker licking his lips and the sides of his mouth as the facial wounds healed and scarred up and this becoming a habit is completely plausible.
If Joker's origin isn't by chemicals in this continuity, why are his teeth all yellow and stained? Well, according to Gordon, he doesn't have any dental records, so logically...
If you pause the scene when the Joker detonates his own henchman in the MCU, you can see a large plume of colored gas erupt from the man before it was ignited. A man who was claiming his insides hurt. That's right, the Joker used him in a "gas attack".
In order to get to Lau, the Joker planned to be caught. However, as planned as it was, it always caught my attention how easily the Joker surrendered after he saw his captor was a very alive Gordon. Lets recap, Batman was unconscious, surrounded by the Joker, someone who is clearly Not Afraid to Die, and 2 or 3 still active goons, then an unidentified police officer points his shotgun at the Jokers neck, who protests asking for some time to play with the Dark Knight. When he gets turned around by the officer, revealing his captor to be no other than Gordon, he surrenders immediately. Then it struck me, the Joker proved time after time to be able to predict and go around the schemers plans. However, Gordon faking his death was something not even he thought of. He easily surrendered because he was actually impressed the then Lieutenant could outsmart him. Gives a whole new meaning to the Joker joining in the applause when Gordon is promoted to Commissioner.
During the boat scene Ginty, the criminal who throws the detonator overboard, was actually pulling a Batman Gambit with the way he approached the guards. He specifically made it ambiguous what he was planning until he did it, with the guards, the other criminals and the viewer assume he was going to blow up the other boat. This means that the only way things will go is that the detonator goes out the window: as long as everyone assumes he's going to use the detonator none of the criminals who actually would use it would interfere with what he was doing and if the guards did have it in them to use it they'd let him have it, so they could tell themselves that a criminal did the act, not them. Conversely if the guard was strong enough to do the right thing they would've thrown it out the window before he could take it, which is exactly what he wanted anyway.
To force the people escaping the city to take the boats, Joker warns them there'll be a surprise for anyone trying to use the tunnels or bridges. Thing is, he wasn't lying. By telling them that he made them expect these places to have been sabotaged and rigged to blow, and therefore would be quite surprised to find that they were perfectly fine to use.
On a bit of a Meta level, the scene where Joker burns the Mob's money, kills the Chechen and Lau, finally declaring open season on Coleman Reese can be seen as a signal to the audience that the Mafia plot is well and truly over. Joker has evolved from an Anarchy-loving mercenary into a full scale supervillain, complete with elaborate and destructive scheme with the goal of driving everyone around him mad. This is the escalation Gordon was talking about in the last movie. After all organized crime depends on subtlety, which is invalidated by the actions of the Joker.
In the same scene where Joker kills Chechen and puts a hit on Coleman Reese, the scene cuts away right after Joker asks "where's the Italian?" He's obviously talking about Maroni, who has just snitched to Gordon. This single line explains why Joker goes about the hospital threat the way he does (in that he gives enough time for the hospitals to evacuate and ensures that everyone except the cops he personally kills comes out alive): he realized that Maroni snitched, and he deliberately made the threat at that exact moment so that the police wouldn't have time to act on his information but would have enough time to divert all of their focus to the threat. He gets to corrupt Harvey, cause chaos and destruction, and, most importantly, doesn't get arrested on the barge, all while keeping his precious rivalry with Batman intact.
Two-Face puts on his seatbelt before shooting the driver. Some say that a seat belt only gives you a 50-50 chance of surviving a car crash. Bet he loved those odds!
Right after The Joker pulls the magic trick, you can see him glance over to the Chechen and Maroni; immediately cut over to Chechen looking impressed at his brazen audacity. It seems clear in the immediate moments he walked into the room, the clown managed to quickly read the room's psychology and correctly identified that he could easily impress the Chechen, might have to work a bit harder to persuade Maroni, but saw that Gambol on the other hand wouldn't be a happy customer.
During the interrogation scene, when The Joker taunts Batman that "tonight you're going to break your one rule", he's actually impersonating Batman's well known growl, for extra effect.
Harvey's Death Seeker status by the end of the movie has many layers, but one the film doesn't point out is that his refusal to have his burns treated with skin grafts pretty much guarantees infection, potentially leading to a nasty death from gangrene and blood poisoning.
During the scene where Harvey is being taken to County, the convoy is diverted by a burning fire truck. If you look closely, you'll notice bunker gear thrown about around it. We never find out what happened to the crew of that truck...
Which sounds more like the Joker: Steal a firetruck to set it on fire and use as a roadblock, or wait for a fire truck loaded with firemen to set on fire and use as a road block?
A bit of Fridge Horror from the comics. Harvey calls the coin his father's lucky coin. Seems like a random line until you realise that in the comics Harvey's dad would flip that coin to decide whether or not to beat Harvey. Heads he would; tails he wouldn't. Now what's unique about Harvey's coin...
"Five dead, two of them cops." That would mean that Dent managed to ice anywhere between one and three people offscreen and that there may have been at least one more corrupt cop in the GCPD besides Wuertz (who is confirmed dead) and Ramirez at the time TDK takes place.
After the Joker tosses Rachel out the window and Batman leaps after her, we don't see what happens next. Presumably, the Joker made a getaway, but being who he is, it's very unlikely he did so without shooting as many people as he could just to piss off Batman and Harvey first.
Joker had a hospital and multiple random buildings rigged to explode, something that would take a lengthy amount of time to set up, yet claims to not have a plan. If he isn't lying about that, that means he's improvising, which would imply that there are even more locations all around Gotham set up to explode (or do something similar) that he doesn't wind up using. How many explosives and death-traps are just left waiting for someone to set off after the end of the movie? More so, with Batman not doing his thing for some time, who's to say anyone is capable of thoroughly looking into this?
The Bat-impostor that was killed by the Joker had scars on his cheeks. Doylist answer: The production team didn't want to push the PG-13 too far by showing his wounds for what they would really look like. Watsonian: The Joker had held the poor bastard hostage and kept him alive long enough for the wounds to heal without treatment.