The song received universal acclaim, with critics complimenting Banks' versatile rapping style as well as her songwriting ability. The Guardian gave the song a positive review and placed it at number 2 on their The Best Songs of 2011 list. In the review, Michael Cragg praised the song, calling it "a startling three and a half minutes of attitude" as well as "incredible." Carrie Battan of Pitchfork Media named the song "best new track", lauding Banks' "unpredictable vocal range" and wrote, "She clicks between characters and styles casually, effortlessly. No seams. A jaw-slackening demo reel." Thomas H. Green from The Independent called it "a potty-mouthed sex song that encapsulates the way the current US explosion in EDM has adapted and adopted European rave, mixing the style with hip-hop and R&B stylistic tics."NME dubbed the song number 18 on their 50 Best Tracks Of 2011, calling it "mischievous, quick-witted and full of filthy cunnilanguage: it’s made Azealia Banks the coolest girl on the planet, and it delivered on 2011’s forward-thinking promise."NPR Music gave the song a positive review and listed it as one of their 100 Favorite Songs Of 2011, calling the song "the raunchiest shut-down of 2011."The Village Voice's Pazz & Jop ranked "212" at number 6 to find the best music of 2011. Pitchfork Media also ranked it number 9 on their Top 100 Tracks of 2011 list, writing:
So she's an internet novelty? Hardly. "212" works because its popcraft and its shock tactics are each other's Trojan horses – concentrate on one and the other sneaks up on you. One reason "ruin you, cunt" feels like such a payoff is that Banks spends an entire verse of quick, unshowy rapping setting up its run of vowels. Banks uses the peaks, breakdowns, and drop-outs of Lazy Jay's bouncy "Float My Boat" to give her Minaj-style vocal-shifts some context: from sassy and chatty during the build ups to cartoon rage as the synths rear up around her at the song's end. If it were judged only on its visceral thrill, "212" would still be one of 2011's best, an unashamed banger in a mostly mid-tempo year. But the more you dig into the song, the more you can hear details and decisions that suggest a scary degree of pop talent.
A music video to accompany the release of "212" was first released onto YouTube on September 12, 2011 at a total length of three minutes and twenty-five seconds. Directed by Vincent Tsang, the video is shot in black-and-white, and features Banks dancing in front of a brick wall and close-ups of her rapping to camera. In addition to Lazy Jay, the video also includes appearances by Québécois record producers Lunice and Jacques Greene.