"The Lock Box": Francis DeGraumont is a smug, emotionless pimp who runs a high end, invitation-only brothel while working for intelligence services to provide blackmail material of diplomats in compromising positions. To do this, DeGraumont is happy to kidnap girls and let them be raped by his clients while secretly recording them. Upon being exposed, his handlers try to have him flee the country, and when a grieving father tracks him down, DeGraumont happily tries to murder him when he's helpless, claiming "self-defense".
"Unnatural Causes": The Orchid Killer, real name Goodheart, is a misogynist who targets middle-aged women, considering them parasites. Upon taking advantage of their loneliness, he gains access to their homes and throttles them with a cord, leaving an orchid upon the corpses. Killing several with a larger body count, Goodheart murders a friend of Robert McCall and later attempts to kill another when she poses as a woman seeking a date to entrap him.
"A Place to Stay":
Mr. Griswald is a street photographer who doubles as a child pornographer. Griswald takes in young runaways off the streets, gets them into modeling for his photography before slowly getting them to strip down, taking a disgusting pleasure in manipulating and grooming them all the while. Most of Griswald's victims end up turning to prostitution on the streets of New York where nothing waits for them but abuse and poverty at best and a cruel death at worst—a prostitute named Judy who befriended one of his latest victims who is later found dead with her skull cracked open was one of Griswald's former young charges. When his latest prey, a 13-year-old girl, discovers what he did to Judy, Griswald throws away any veneer of niceness and advances on her.
Peter Marstand is a magazine mogul serving as Griswald's boss. Alongside his legitimate business, Marstand peddles Griswald's child pornography across the criminal underworld, sampling pictures during work and at one point visiting Griswald personally during a photo shoot and impatiently urging him to get to what he considers the good part. A picture of Marstand in bed with one of the children evokes a murderous rage from Robert McCall seldom seen since and a promise that if Marstand should buy his way out, McCall will take care of him personally.
Retroactive Recognition: The show had quite a number of notable guest stars, many of whom became major stars within a few years of their appearances:
Eight-year-old Macaulay Culkin appeared in "Something Green" as a kidnap victim.
Nine-year-old Melissa Joan Hart appeared in "Torn" as a young girl whom McCall protected from her ex-con father.
Christian Slater appeared as a high-school student in "Joyride".
Ed O'Neill played a doctor in the first season episode "The Children's Song".
John Goodman played a single father who was tricked by co-worker Joe Morton into taking part in a robbery in "Re-Entry". Goodman's frequent co-star Steve Buscemi appeared in the same episode, which marks the first time the two were on screen together.
Goodman's future Roseanne/The Conners co-star Laurie Metcalf played a secretary involved with industrial espionage in "No Conscience".
Vincent D'Onofrio appeared twice in the series, playing the arsonist son of a mobster in "Counterfire", and a mentally-challenged man falsely accused of murder in "Suspicion of Innocence".
Values Resonance: The original series depiction of stalking as a serious, threatening crime. As author Martha Wellswrote, “In 1985 stalking was barely acknowledged as a crime, even though every woman I knew on campus had been stalked or harassed at some point. And if you complained about it, everyone believed it was your fault, you asked for it somehow. […] The Equalizer was the first show I saw that said stalking was a crime, it should be punished, and it wasn't the victim's fault.”
Complete Monster: Slavi is a pimp in the employ of Vladimir Pushkin and an especially revolting Starter Villain for Robert McCall. Slavi raised a girl named Alina as a prostitute from the time she was a little girl, raping her himself whenever he's not turning her over to others. When Robert inspires Alina to fight back, Slavi beats her half to death and muses next time he'll cut her throat—"maybe a whore who fucks and doesn't speak will make twice as much." Even an offer of nearly ten grand isn't enough to sway Slavi from his vile hold on Alina.
Ensemble Dark Horse: The bearded henchman in the climax, as he is notably the only character in the entire series to actually give McCall some trouble as well as put up a rather decent fight.
Escapist Character: Who secretly doesn't want to be a seemingly unstoppable, resourceful badass, fighting off rooms full of gun toting gangsters with their bare hands, barely breaking a sweat sometimes, and getting justice for their victims, without needing any of those silly superhero powers? Not only that but the guy isn't exactly young either.
Robert McCall is pushing sixty, but fully capable of killing people with the contents of a room, finding out virtually everything about you, and will destroy everything you have if you don't listen to him. Thank God he's one of the good guys and he only does this shit to really bad people who hurt and abuse others.
The battle in Home Mart is basically a scene from a slasher movie put into a action film; Robert turns off all the lights and begins eliminating the mooks in Jason Voorhees-esqe ways like hanging a guy with a barb-wire noose, putting hedge trimmers through another's neck, and putting a drill through a mook's head. The barb-wire hanging is particularly chilling as Robert stares at the mook with cold rage as the man is strangled and bleeds out.
As well deserved as it is, Slavi's death is this trope, not because of how he was killed, but his last moments when Robert coldly tells him how this all could've been avoided by just leaving Alina alone, and now, he's going to die on the floor while she lives another day. Then, the audience gets a POV view of Slavi's vision blurring as Robert counts down his last seconds.
The Woobie: Alina. Forced into prostitution, and clearly doesn't enjoy what she does, but doesn't have any way to escape. Even sadder when she's shown interacting with McCall, and the audience gets a glimpse of the normal teenager she could have been. Also she loses her friend Mandy when Teddy strangles her to death. Fortunately, she's able to survive her injuries, and by the end has started to go to school and has a safer job.
Stewart Copeland's early work on the series' soundtrack - including its signature opening theme