Affably Evil: Well, that's how the Devil tends to operate anyway.
Faux Affably Evil: However, some of the demons working for him are not likable at all. Milton himself while being charming and polite, he's also a 100% sadist soul.
All Just a Dream: In the final scene, it is revealed that Kevin saw the entire movie in the moment before his career-defining case about a child molester. Even though he does the right thing and refuses to win the case, Milton is still lurking around and manages to tempt him yet again.
Another interpretation is that Milton reverted time back to the point before Kevin's career-defining case in order to keep trying alternate pathways until he can get to the point where Kevin submits. There's also the implication that Milton will do this as many times as necessary until he wins.
Ambition Is Evil: Played straight. Kevin's ferocious commitment to winning his court cases results in him defending some rather unsavory characters, and costs him his marriage.
Not to mention Kevin revealed to Milton that he won all his Florida cases by secretly listening in on how the Jury was deliberating and making the proper adjustments.
Amoral Attorney: Satan himself runs an entire corrupt legal office with global connections, composed of immoral humans and his own demons. An explicit example is the protagonist, Kevin Lomax: while he does retains some moral qualms against defending a pedophile in the beginning of the movie, he more or less completely eschews them and becomes this trope.
Big "NO!": Possibly the Biggest No ever. It takes several cuts, several breaths, and causes the guy to burst into flames and then burn or desiccate anyone watching. Of course, this had to be Satan himself.
Breaking the Fourth Wall: At the end of the movie, after the reporter turns into Milton, he turns to the camera and says, "Vanity, definitely my favorite sin."
The Cameo - Sen. Alphonse D'Amato, Ambassador Charles Gagano, and Don King all appear as themselves, and seem to be on very good terms with John Milton. Makes you wonder if anyone told them...
If they were in fact aware of what kind of movie they were in, it makes for a rather extraordinary case of Adam Westing.
Chekhov's Gun: A literal example. Alex Cullen starts carrying a gun after receiving death threats, which Lomax takes from him as it looks like a tacit admission of guilt. It comes in handy in the climax.
Chekhov's Gunman: The reporter from the Florida courthouse, who's another face of Satan and is able to manipulate Kevin twice. "Vanity, definitely my favorite sin."
Deep South: The movie opens in Gainesville, Florida. Or rather, a small rural town that looks nothing like the actual, modern, skyscraper-encrusted college-town that is the real Gainesville, Florida, but does look like a one-horse hick town in the middle of nowhere, which was probably the point.
Apparently the producers wanted Reeves' character to be from a small rural town and picked Gainesville, Florida off of a map at random, not realizing that "small rural town" does not describe Gainesville, and hasn't for about a hundred years. The Civil War-era "courthouse" where the trial was taking place is actually in a one-stoplight town some thirty-two miles east of Gainesville, for example; the courthouses in Gainesville proper are all modern, multi-story buildings.
Driven to Suicide: Both Kevin's wife and, later, Kevin himself. However, it's revealed to be just a dream, or possibly Satan turning back time to try another way. Or, it could be that God turned back time in order to give Kevin another chance to make the right decision.
Also the scene in the changing room, where the Devil's girls strip down to their underwear while casually making Mary-Anne as uncomfortable as possible and... AUGH! BAD FACE! BAD FACE!
Christabella's role in the ending is probably supposed to have this effect, all things considered, but frankly, it's hard to turn a naked, willing Connie Nielsen into a source of disgust.
Evil Cannot Comprehend Good: Satan, whose entire modus operandi is based on hatred, never considered that love would be important to Kevin, and that he'd remember Mary Ann as his best friend rather than as just a sex object and thus reject Christabella. But it could all be just an act from milton to make Kevin feel like he's the hero, while he is still as morally weak as before...
Hollywood Law: Kevin's courtroom antics wouldn't exactly pass the bar in reality. Some of it might be justified given the revelations at the end.
In the initial case with the child molester he presents some surprise evidence. This should have been presented during the pretrial discovery and would have resulted in sanctions against the defense and possibly a mistrial.
Kevin is presented as having never lost a case. This phenomenon is seen commonly among new lawyers that haven't tried any cases, and never outside of that. In Milton's rage-against-God speech near the end he even lampshades how impossible it is for a lawyer to have never lost a case and points out how supernatural influences were a factor.
Kevin would not be disbarred for his actions at the end of the movie; in fact, he would be required to withdraw in that case as his client was using his services to further a criminal act.
Hollywood Voodoo: Kevin's first case with Milton's firm involves defending a man who was caught slaughtering a goat in the practice of Santeria. The actual case (and Kevin's defense of religious freedom) are completely plausible and justified. However, the client's use of a curse against the prosecutor and other hints at supernatural powers... stretches the imagination.
I Have Many Names: Pretty much word for word. Though Pacino plays with this a bit. No need for the fancy titles, he just wants Kevin to call him "Dad."
Important Haircut: Important, but not at all good. Mary Ann gets a haircut after prompting from Milton, and this just destabilizes her even more.
In the End, You Are on Your Own: After Mary Ann kills herself and Kevin realises what he has to do, he heads for the final confrontation on foot, because Manhattan is suddenly and inexplicably uninhabited.
Not Even Bothering with the Accent: Reeves starts off his performance affecting a passable Southern accent, appropriate for Lomax's Florida background. It vanishes rather quickly.
Obvious Second Choice: Evidently the filmmakers wanted to end the film with "Sympathy For The Devil" By The Rolling Stones. It would seen they had to settle for less appropriate "Paint It Black." (your Mileage May Vary)
One-Winged Angel: Almost completely literal, as Milton transforms into a Fallen Angel at the climax. (His minions, too, occasionally enjoy flashing fanged grins out of their otherwise perfectly human faces.)
Post Rape Taunt: "Well, on a scale of 1 to 10 — 10 being the most depraved act of sexual theatre known to man, 1 being your average Friday night run-through at the Lomaxes' household — I'd say, not to be immodest, Mary Ann and I got it on at about... seven.
Pride: The theme of Pride/Vanity as an engine of destruction runs all through the plot of the film, namely because it makes you careless and imprudent or just drags you into the affairs that will surely and painfully bite you in the ass. Even the father of the sin himself is not invulnerable to its pernicious influence. At one point, he describes it as his favorite sin and the most "natural" as it stems from a "love of self".
Sanity Slippage: Mary Ann starts out as much of a go-getter as her husband, but between being becalmed in their huge apartment, the shallowness of the other wives, and the evil surrounding them, she unravels completely.
Seven Deadly Sins: The story focuses on Pride for the better part of the film (it is the devil's favorite sin), but the others are represented at various points throughout the film.
Kevin lusts after Christabella.
He also shows a bit of sloth in not actively doing what he knows is right during more than one case.
Greed rears it's head in the riches that Kevin is granted... as long as he keeps bending the rules.
It could be said that envy is part of the reason that Kevin goes along with everything. He wants what others have in the field of law. The fame, the riches, the everything. No matter how he has to get it.
Lucifer tells him he could have stopped at any point and even gave him multiple options to stop, but Kevin didn't want to, showing his gluttony.
Lucifer goes mega wrath after Kevin makes his choice. "Free will."
As stated, pride is the whole point. It is the devils favorite sin. Pleased to meet you, won't you guess my name?