!!The film contains examples of:

* AlternativeCharacterInterpretation: Possibly overlapping with FridgeBrilliance; Capone's lawyer, at the end, immediately enters a plea of guilty as soon as the judge orders the bribed jury swapped out for another one. The lawyer does this without Capone's consent which, as noted on this wiki and elsewhere, is grounds for an immediate mistrial in real life. Anyone ever consider that said attorney knew this and pulled the stunt as a Hail Mary to get Capone off once he knew it was otherwise all over?
* ClicheStorm: The amount of tropes this film plays remorselessly straight (among other things, TheMentor, NeverHurtAnInnocent, SacrificialLion, ManOfWealthAndTaste, TheSquad, YouHaveFailedMe, BlackAndWhiteMorality, VeryLooselyBasedOnATrueStory, etc) can be rather jarring to to some modern viewers. But seeing how popular the film became in its day, and what a great following it still has, [[TropesAreNotBad it wasn't necessarily a bad thing]].
* CompleteMonster: Frank Nitti is presented as a PsychoForHire for UsefulNotes/AlCapone. Introduced early on as Capone's main enforcer and hitman, Nitti is seen bombing a restaurant with a little girl inside, not caring that she's killed as well. Through the film, Nitti handles Capone's wetwork, ruthlessly murdering anyone in his way with barely disguised relish, continuing to eat his meal even as the man right next to him is having his brains bashed out by Capone, slaughtering both Oscar Wallace and the Capone man apprehended by the squad and writing "touchable" on the wall in their blood, and later gunning down tough Irish cop Malone. He threatens Elliot Ness's family if he won't drop his case. Nitti later tries to rub his own status as untouchable in Ness's face, even taunting him that Malone "died screaming like a stuck Irish pig," which finally makes even the composed Ness snap ([[spoiler:leading Ness to throw Nitti off the roof, with Ness taunting Nitti as he falls screaming to his death]]).
%%Do NOT add CompleteMonster entries without going to the cleanup thread first.
* ConsolationAward: A conversation in the film ''Literature/{{Trainspotting}}'' suggests that Connery received the nod for Best Supporting Actor for this reason.
* HilariousInHindsight:
** In this film, Creator/SeanConnery's character frequently says you should NeverBringAKnifeToAGunFight. Not long afterwards, Sean would star in ''Film/IndianaJonesAndTheLastCrusade'' as the father of Franchise/IndianaJones, a man that always brings a gun to knife fights. Further, in that film, Connery's character successfully wins a fight against a fighter plane with an ''[[ImprovisedWeaponUser umbrella]]''.
** Similarly, Austrian-born actor John Banner appeared on the TV show as a Bavarian brewmeister, who is later confronted by a fellow brewmeister - whose brewery was rushed by the police - to see what he knows about any of it. [[Series/HogansHeroes He knows nussink! NUSSINK!]]
* LawfulNeutral: Jim Malone. "Because I swore to uphold the law. . .".
* MemeticMutation:
** "I want him dead! I want his family.. dead!"
** "You're nothing but a lot of talk and a badge!!"
** The whole "How to get Capone" speech.
** "Somebody messes with me, I'm gonna mess with him."
* SpecialEffectFailure:
** Toward the end of the bridge scene, Ness throws a frag grenade at one of the gangsters, which then explodes. Even on a first viewing, it's apparent that the grenade itself does not blow up, but rather a separate charge buried directly behind it.
** The green screen effects during [[spoiler:Nitti's death scene]] are pretty noticeable as well.