"My actions don't require any defense. In the same situation, I'd do it again. [...] As individuals, and even more so as a group, the Justice League is far too dangerous to lack a failsafe against any misuse of our power. [...] What if we ever use it for some other purpose? If you people can't see the potential danger of an out-of-control Justice League, I don't need to hear a vote. I don't belong here." —Batman
Adaptation Explanation Extrication: In the original comic storyline, Batman was able to better defend his position by citing an incident where supervillains swapped bodies with the Justice League. While he was still being paranoid, that incident proved he was speaking from experience. In this film, we never get any indication that a similar situation happened or could happen in this universe, and we are just supposed to take Batman at his word that he has a point. There is a sequence where a drug-addled Wonder Woman attacks innocent civilians, but she wouldn't have been in that situation if Batman hadn't made the contingencies.
Adapted Out: The movie replaces Wally West with Barry Allen, Kyle Rayner with Hal Jordan, Aquaman and Plastic Man with Cyborg, and Ra's al Ghul and the League of Assassins with Vandal Savage and the Legion of Doom.
All There in the Manual: The film assumes that the viewer has some cursory knowledge on each superhero and their Rogues Gallery. Each villain is given very little backstory, even the more obscure ones like Mirror Master and Ma'alefa'ak. The biggest example is probably Green Lantern's trap and his interactions with Star Sapphire, which are completely based on their sharedbackstory—but said backstory is barely even alluded to.
Apocalypse How: Vandal Savage plans to control this by using a device to incinerate the sun facing side of the planet, while ruling over the other.
Artistic License - Physics: Vandal Savage plans to launch a rocket at the sun which will create a solar flare. A magnetic trail left by the rocket will guide the flare back to Earth. When implemented, this fails on several points. The rocket gets there at practically the speed of light, even though by all appearances it's an ordinary rocket. Superman can catch up to and keep pace with it, not to mention shooting at its warheads with heat vision despite the speeds involved. The solar flare is also blocked by Green Lantern, yet that only stalls it as opposed to dissipating it.
Superman offers to move the Earth out of the way of the flare, playing it straight, but Batman immediately cuts him off, saying it would take a week to explain why it wouldn't work.
Bare Your Midriff: Oddly enough, the only members of the Legion who have shirts covering theirs are Savage and Mirror Master. Granted, Metallo is a robot, and technically, Mirror Master's costume is transparent around the belly... it's just that his torso is transparent, too.
Bittersweet Ending: Savage is defeated, the world is saved, all the Leaguers come out alright and Cyborg becomes a member of the league... but the League's faith in Batman is shattered and he himself quits when called out on his actions. That said, it ends a lot better than the comic it's based on. Here, it's played like a semi-amiable conflict of interest (especially when Superman is involved), in the comic it's a total schism which near shatters the trust of the entire League and has ripple effects to other teams around the DC Universe.
A villainous example. When Ma'alefa'ak, disguised as a human woman asks John Jones for a light, he replies "I don't smoke." After poisoning J'onn to make his skin secrete magnesium and setting him on fire to burn to death, he casually walks out of the diner, scoffing "He 'doesn't smoke...' "
Wonder Woman says one after defeating Cheetah.
"You're good, but lately, I've had a lot of practice fighting you."
Bane's first fight against Batman is a Curb-Stomp Battle that ends with him dumping the still-living but quite unconscious Bruce Wayne into the grave of one of his parents and burying him alive. If he had simply killed him then and there rather than deciding to humiliate him, the Legion of Doom would probably have won.
If Star Sapphire had killed Green Lantern while he was vulnerable during his Heroic BSOD, the bad guys would likely have succeeded.
Metallo simply shoots Superman once and pushes him off the roof, then goes back to hang around the swamp. Vandal Savage has unlimited wealth, and he couldn't afford more than one kryptonite bullet?
Why did Mirror Master put conditions on when the wrist bomb could detonate? It's not like he has to worry about his own safety, since he's not even there. He should've detonated it as soon as it was locked in. This one, at least, can be attributed to the bomb being of Batman's design, and wasn't intended to be lethal.
Break the Haughty: Batman actually refuses to surrender to this trope, mostly because his ego won't let him.
Batman. This proves to be the impetus for the plot, as Batman had made plans to take down the League just in case. The others see it as paranoia, but he sincerely believes that all of them need to have something that can take them down just in case the worst happens - even himself. And considering the readiness with which he countered the plans, it's likely that Batman also had contingency plans for the contingency plans.
Vandal Savage. The missile actually sets off a Macross Missile Massacre? Okay, fine, not that crazy. Turns out that the individual missiles can launch their own missiles.
Superman gets two. In the first, when fighting the Royal Flush Gang, the super-strong Ace slams the Man of Steel with a huge vault door. For a moment it seems Supes has taken some serious damage, but that's only because the focus switches to the other Leaguers' battles. When the attention returns to Superman and Ace, the former blasts through the vault with his heat vision, then simply stands there while Ace ineffectually pounds at him until Ace literally breaks his own arm off. Then Superman catches the other fist, crushes it, and finally tears Ace in two with one punch. In the second, it's Superman vs. Metallo. At first this one looks like it might be an actual fight, as Metallo has Kryptonite and briefly has the upper hand — until Superman decides he has more pressing matters to attend to, smashes the Kryptonite compartment shut, and simply decapitates Metallo with his heat vision.
Bane's first fight against Bruce also counts. Bruce only survives because of Bane's Bond Villain Stupidity, as explained above.
Dangerously Genre Savvy: Vandal Savage. While every other supervillain would build a single missile, thus allowing his plan to be foiled just by destroying it, Vandal puts smaller missiles in his big missile, and then puts smaller mini-missiles inside those missiles.
Darkest Hour: When Superman is shot with a kryptonite bullet and falls from the top of the Daily Planet tower, shots of him falling are interspersed with shots of the rest of the Justice League facing their own apparent demises.
Eye Beam: Jack of the Royal Flush Gang. And of course there's Superman's heat-vision, which is the deciding factor in his second fight with Metallo.
Fashionable Asymmetry: Several characters; Cyborg (even more than usual), Bane, Metallo, etc. Even Savage wears an asymmetrical tooth on a gold chain.
Genre Savvy: Jack of the Royal Flush Gang. While far from Dangerously Genre Savvy, he's Genre Savvy enough to realize that someone needs to be on lookout for superheroes during the robbery.
Gender Bender: Ma'alefa'ak transforms into a hot blonde woman to tempt the Martian Manhunter into lowering his guard.
Gory Discretion Shot: Most of Wonder Woman's scenes when she's infected are from her perspective, so we see the cops, civilians, and Cyborg as Cheetah for the most part. We conspicuously don't have her viewpoint, however, when she rips off Cyborg's arm.
We also don't see the actual slash across the throat when Cheetah tests Savage's immortality. The blood (from behind), him falling, lying facedown on the floor, the marks healing, yes.
Heroic BSOD: The plan to take down Green Lantern involves putting him in one of these with lots of trickery and a healthy dose of fear gas.
Hero Insurance: Wonder Woman clearly has her premiums paid up. Cheetah uses some Applied Phlebotinum to force Diana to see everyone around her as Cheetah, causing the Amazon to assault what may be dozens of civilians and cops, not to mention ripping off Cyborg's arm. Cyborg snaps her out of it, but still, she's committed a good number of assaults of Muggles and never gets called on it. Well, not to her face.
Idiot Ball: In-story, Green Lantern accuses Batman of carrying the ball. GL's actually okay with the idea of Batman having contingency plans to take down the League; what he objects to is Batman letting those plans be stolen.
Lady in Red: A blonde woman in a red dress J'onn meets in the bar. It was Ma'alefa'ak in disguise.
Leeroy Jenkins: In the beginning, Superman asks Batman to wait for backup, but Batman shuts off his communicator and charges in. The Royal Flush Gang kicks the crap out of him before the Justice League shows up.
Little "No": From Superman, when the last bit of Savage's missile escapes him and the deadly solar flare begins.
Similarly, Superman's plan of moving the Earth out of the way is a call back to the episode "Invasion of the Fearians" where Green Lantern did the same thing to save it from Sinestro's comets. It did more harm than good.
Neck Snap: Bane does this to an alligator that attacks him.
New Powers as the Plot Demands: A story where limits to each superhero are revealed and exploited allows a solid aversion of this trope. Even once the heroes make their comeback and then try to save the entire world, it takes more intellect (and some Applied Phlebotinum) rather than superpowered brawn to come up with a plan that succeeds.
Nice Job Fixing It, Villain: Bane's arrogance essentially leads to the downfall of the Legion. Burying Batman alive with his parents is really only going to serve to remind him why he's Batman and piss him off. Batman himself lampshades this.
No Badass to His Valet: In the opening battle sequence, Batman gets pretty badly hurt, but being Batman wants to shrug it off and keeps working. Wonder Woman offers to let him use her Purple Healing Ray to cut down his recuperation time; he ignores her. But when he's back at the Batcave, Alfred insists that he rest and get medical care, and stares him down.
The entire Legion when Savage gets up after Cheetah slashes his throat.
Batman, when he realizes that his contingency plans are being used against the League.
Ma'alefa'ak when Savage's missile ignites in his face.
Ten in the first battle, literally: "Crap! It's the Justice League."
OOC Is Serious Business: The way in which Hal is taken down seems very out of character for him, since the ability to overcome great fear and doubt are job requirements for Lanterns, but it's actually a plot point— Hal had fear toxin used on him in addition to having his greatest failure recreated.
Outrun the Fireball: Flash, after vibrating the bomb off his wrist. Being the Fastest Man Alive, of course, means he literally can outrun the fireball (though the shrapnel wings him).
Power of Trust: A major theme. Though it's not quite as shattered as in "Tower of Babel," mostly as it isn't revealed until well after he's gone out of his way to save them all, the team's trust in Batman is wavered by the fact that he made the plans against them in the first place. In the end, however, it leads to a heartwarming moment of sorts where it's shown that even though they don't like his methods they, particularly Superman, still trust him to do what's right even if it's against them, and likewise Batman trusts the League to counter him should he go too far.
Provoke Me Taunt: Green Lantern delivers one to Ten after the first warning shot.
The Stoic: Ma'alefa'ak. While the rest of the Legion celebrates the apparent destruction of the Justice League, he simply leans back without a word. He only loses his cool when Martian Manhunter is revealed to be alive, and when the missile ignites in his face.
Martian Manhunter as well. When King knocks him out, he just looks up and says, completely deadpan, "I am unharmed". He loses his cool when Ma'alefa'ak attacks him, but in his defense it's hard to remain calm when you're on fire.
Stripperiffic: Star Sapphire in her current costume (actually nowhere near as much as some of her other more recent costumes).
Superman Can Breathe In Space: And he also talks too. Well, he does have super breath, he could theoretically produce the air needed to speak in space himself. Or he's just using communicators.
The Legion of Doom, to an extent. Savage is the only one explicitly said to be in prison. Ma'alefa'ak is likely dead, given his proximity to the missile when it launched, and one could assume the other five were arrested, but it's never brought up.
What the Hell, Hero?: Pretty much the entire League's reaction to Batman's holier than thou refusal to admit he was wrong or at least responsible for innocent people being hurt. Wonder Woman begins to give Batman one of these speeches, but is cut off. Superman finishes it, calling the Dark Knight "arrogant" to his face.
Whip It Good: How Wonder Woman uses her Golden Lasso. It's actually used as a whip more than it's used as a lasso, and the lasso's loop often disappears entirely, apparently creating the loop whenever it's needed.
The Worf Effect: Happily averted. When he's in an ensemble, Superman often goes down very easily to emphasize how dangerous an opponent is; early seasons of Justice League were especially bad about this. But in Doom, he's clearly the team's strongest member, offering to move the entire Earth and easily outstripping a solar flare traveling at light speed.
As described under Curb-Stomp Battle above, Superman appears to fall victim to this in the battle against the Royal Flush Gang when the battle starts with Ace flattening Supes under the vault door. But in the end, it barely slows him down.