Camp: Guess who? Especially when Mercutio performs in drag at the Capulets' party.
Notably, the Montagues don't wear vests, favoring unbuttoned Hawaiian shirts, as a sign that they're not intimidated by the Capulets.
Bulletproof Vest: Most, if not all, of the younger Capulets wear bulletproof vests styled to look like waistcoats.
Broken Record: The "either thou, or I, or both must go with him" line said by Romeo to Tybalt once in the original is screamed over and over again in this version.
Boss Subtitles: Every time a new character is introduced, their name and role within the houses are shown (likely for the benefit of those who havent seen the play before).
Even his pistol's magazines have the Capulet family crest on them. Tybalt's Rapier 9mm particularly stands out.
Bling-Bling-BANG!: Romeo, Sampson, Mercutio and Tybalt carry some of the most elaborately decorated pistols in film history with gold plating, custom magazines with family crests and decorated grips.
Black Dude Dies First: You got it - Mercutio.
Big "NO!": Romeo after Mercutio's death.
Big Brother Worship: Romeo's feelings towards Benvolio, who is actually his cousin and not his brother.
When Romeo tries to introduce himself, he startles her so much they both fall into the pool. Romeo quickly ducks out of sight, but then Juliet exits an elevator on the ground floor, so he doesn't have to climb anywhere.
Balcony Wooing Scene: Spoofed when Romeo climbs up to Juliet's balcony for the famous scene.
Bad Guys Play Pool: Well, the rivaling Montague clan plays pool while watching news reports on TV.
A-Team Firing: When Romeo returns to Verona, neither he nor the police land a shot on each other.
Anachronism Stew: One of the most memorable parts of this adaptation is that the setting has been modernized but everyone still speaks in Shakespeare's famous flowery dialect.
Tybalt manages to provoke Mercutio into hostilities with a homophobic taunt of "Mercutio! Thou consortest with Romeo!", removing a considerable amount of ambiguity to many viewers. Quickly subverted seconds later as the two enter an elevator and kiss in there.
Almost Kiss: The second time Romeo and Juliet try to kiss, they are interrupted by the ding of a bell.
Guns carry brand names like "Dagger", "Sword", "Rapier" and "Longsword" to keep within Shakespeare's original script. Romeo's age was unspecified in the play, but he's also 16 years old in this movie.
Age Lift: The 13-year-old Juliet in the play is now a 16-year-old Lord Capulet's mention of her being less than 14 is noticeably cut.
Adaptation Name Change: Abra (originally Abram or Abraham, a servant of Montague in the original play), now associated with the Capulets.
Although, since there is no real indication that Mercutio is related to Captain Prince, it is possible that, through context change, "a brace of kinsmen" might mean "some fine officers". But Paris is (apparently) still alive and doesn't seem to be related to him, which raises the question of who the other "kinsman" he lost is.
Adaptation-Induced Plot Hole: At the end, Captain Prince claims to have "lost a brace of kinsmen", as he does in the play, in reference to Mercutio's death.
Lord Capulet verbally abuses Juliet when she won't marry Paris in the play, but never physically hurts her or his wife.
He also engages in a shoot-out with the police at the climax. Here, Romeo chases Tybalt down quite violently, and shoots him repeatedly in (more or less) cold blood. In the play, Tybalt returns to the scene after killing Mercutio, and Romeo kills him in a duel.
Tybalt starts beating up Romeo when the latter refuses to fight him, forcing Mercutio to intervene.
In the movie, where Paris is Spared by the Adaptation, he says it when taking a Human Shield against the VPBD SWAT cops outside the vault.
Romeo originally said the line "Tempt not a desperate man" when confronting Paris in the Capulet family vault.
In film, he only says it after "Ay, ay, a scratch, a scratch", upon realizing the wound is fatal.
In the original play, Mercutio said "A plague o' both your houses" immediately after being stabbed.
He says the line before Mercutio's big song. Here, it is moved to the ball scene, where "Queen Mab" is actually a drug-analogous to Ecstasy-given to Romeo by Mercutio.
Romeo's line "thy drugs work quick" was originally his second-to-last words before he died from suicidal poisioning in Juliet's crypt.
The lines and motives of Benvolio and Tybalt are not changed, however.
In the first scene, the lines of the servants of Montague and Capulet are changed, so it is the Montagues that offend the Capulets, not the other way around as in the original play.