- Alternative Character Interpretation: Were Stansfield's men just as flat out corrupt and gleefully evil as their boss, or were they simply too lazy to do their jobs honestly and became too scared of Stansfield to oppose him as he became more extreme over time? While Stansfield's team appear inept and don't seem to have qualms about corruption and police brutality, it's notable that Malky unsuccessfully attempts to rein in Stansfield's behaviour several times. They're also alarmed when Stansfield crosses their line of fire in the apartment raid, and his drugged up behaviour gets uneasy glances in the corridor. Coupled with Stansfield snatching Malky's gun, this suggests that his wholesale slaughter of the family was not what they were expecting or even planning. However it's noticeable that Willie Blood, the dreadlocked cop shows almost no reaction to murdering an innocent child, they chill in relaxed fashion in their office later, perhaps hinting they really are all rotten to the core after all.
- Awesome Music: Sting's "Shape of My Heart", the end credits theme.
- Better on DVD: The Director's Cut is universally considered to be the superior version, as it delves more into the relationship between Leon and Mathilda.
- Complete Monster: Norman Stansfield is a psychotic DEA agent who takes advantage of his position to terrorize, extort and kill who he wants. On a drug bust, Stansfield, after finding out that Mathilda's father has been cutting the stashed cocaine he gave him, decides to get high on drugs and slaughter Mathilda's family, including her baby brother, only caring about how he'll explain the deaths to his superiors. Foiling Mathilda's plan to kill him, he attempts to kill her while she's crying, taking pleasure in killing people who value their life. When Leon kills one of his men during a drug deal and rescues Mathilda, Stansfield leads a raid on Leon's apartment with the intent to kill the two, later shooting an injured Leon In the Back before he can escape, fatally wounding him in the process.
- Crosses the Line Twice: Stansfield is so over-the-top with his violence, from pausing a massacre to lecture someone about classical music to shooting at an old lady for not going back into her apartment when told, his psychosis is often as amusing as it is horrifying.
- Hilarious in Hindsight: Stansfield constantly talking about how much he loves Beethoven was quite appropriate in that Gary Oldman starred as Beethoven in Immortal Beloved, which came out later the very same year.
- Love to Hate: Norman Stansfield is a raging, psychotic, drug-addicted, Dirty Cop who will kill at the drop of a hat. However, thanks to Gary Oldman's incredible over-the-top and oftentimes funny performance, it's almost impossible not to love him as a villain.
- Memetic Mutation:
- Moral Event Horizon: Stansfield crosses it fairly early on, when he kills Matilda's family.
- Léon's slow-motion, cross-eyed roar, seemingly apropos of nothing, right before his room gets hit with a grenade.
- Oldman's performance of Stansfield can occasionally slip into this, depending on who you ask.
- Nightmare Fuel: Norman Stansfield: A drug-addicted psycho with the law on his side.
- Retroactive Recognition: Adam Busch, best known as Warren Mears from Buffy the Vampire Slayer, has a bit part in the film.
- Special Effects Failure: Stansfield discovers the grenades in Leon's vest. Cut to outside, where one of the cars blows up before the explosion happens in the building itself.
- Squick: The underage Mathilda being attracted to the forty-something Léon. Some feel that this aspect of the plot gives the film an unpleasantly pedophiliac edge, particularly in the director's cut. Especially so in light of recent allegations of sexual assault against the director.
- "Weird Al" Effect: Those who are not familiar with this film will believe that the "Get me everyone!" line originated in the 2005 video game Need for Speed: Most Wanted.
- The Woobie: The main characters. Léon especially, who even as a hired killer, behaves rather childishly and innocent. He drinks milk, waters potted plants and watches old musicals with the look of a fascinated boy.
YMMV / The Professional