Cinco de Mayo (Brooklyn Nine-Nine)

According to Nielsen Media Research, the episode was seen by an estimated 1.83 million household viewers and gained a 0.6/3 ratings share among adults aged 18–49. This means that 0.6 percent of all households with televisions watched the episode, while 3 percent of all households watching television at that time watched it.[1] This was a 10% increase over the previous episode, which was watched by 1.65 million viewers and a 0.5/3 ratings share.[2] With these ratings, Brooklyn Nine-Nine was the fourth highest rated show on NBC for the night behind Law & Order: Special Victims Unit and two Superstore episodes, fourth on its timeslot and eleventh for the night, behind Law & Order: Special Victims Unit, S.W.A.T., two Superstore episodes, Life in Pieces, Station 19, Mom, Grey's Anatomy, Young Sheldon, and The Big Bang Theory.

With DVR factored in, the episode was watched by 2.68 million viewers.[3]

"Cinco de Mayo" received critical acclaim from critics. LaToya Ferguson of The A.V. Club gave the episode an "A" rating, writing, "So it should come as no surprise to anyone that the Halloween Heist episodes are the hardest ones for the Brooklyn Nine-Nine writers to write, because especially as time goes on, these are episodes that rely on twists and red herrings and betrayal and intricate plotting. Even if they're extremely absurd moments, like Scully busting through a two-way mirror or the secret tasers or… everything that happens to Terry. These episodes are also even more stuffed full of jokes (typically of the insult variety) than most Brooklyn Nine-Nine episodes, and when it comes to quoting them, it's almost impossible to stop. But that's also part of the Heist's trick, because the joke machine helps make moments like the proposal and Terry acing the Lieutenant exam function as an added surprise, a good-spirited one in an episode full of deception and insults. It all just works."[4]

Alan Sepinwall of Rolling Stone wrote, "Now, everyone goes to such ridiculous lengths to try to win this year that I might worry there's nowhere left to take the heist in Season Seven. But I've had that fear before, and the heist episodes keep working. Even the show seems aware of the pressure to keep topping the last one. 'Five heists was enough,' Rosa insists early on in this one. 'Literally nothing new can happen.' But something new did happen, and it was delightful. So I look forward to what comes next, presumably closer to the actual Halloween."[5] Nick Harley of Den of Geek wrote, "The Cinco de Mayo heist was a clever way to explain why the game wasn't taking place on Halloween and proof that these reoccurring episode formats still have plenty of life left in them. There were more surprising twists and turns in this episode than there have been in the entire season so far. God bless the Halloween Heist, and hopefully with the show coming back for season seven, will get another at the correct time of year in five months."[6]