Halloween IV (Brooklyn Nine-Nine)

In its original American broadcast, "Halloween IV" was seen by an estimated 2.05 million household viewers and gained a 0.9/3 ratings share among adults aged 18–49, according to Nielsen Media Research.[1] This was a slight decrease in viewership from the previous episode, which was watched by 2.13 million viewers with a 0.9/3 in the 18-49 demographics.[2] This means that 0.9 percent of all households with televisions watched the episode, while 3 percent of all households watching television at that time watched television. With these ratings, Brooklyn Nine-Nine was the highest rated show on FOX for the night, beating Scream Queens, New Girl, sixth on its timeslot and twelfth for the night, behind The Real O'Neals, The Flash, NCIS: New Orleans, Fresh Off the Boat, The Middle, Chicago Fire, Bull, American Housewife, NCIS, The Voice, and This Is Us.

"Halloween IV" received critical acclaim from critics. LaToya Ferguson of The A.V. Club gave the episode an "A" grade and wrote, "'Halloween IV' is so overwhelmingly funny — in a way where every character has something to do, which Brooklyn Nine-Nine can sometimes have trouble with — that it takes hold of all the audience's (and characters') sensibilities for the 20-plus minutes of action."[3]

Dan Snierson of Entertainment Weekly wrote, "After three episodes of the witness-protection program in Florida and one episode of night duty, Brooklyn Nine-Nine returned to its comfort zone with something familiar and unpredictable: the annual, zany, twist-upon-reversal-upon-fake-out Halloween heist episode."[4] Allie Pape from Vulture gave the show a 4 star rating out of 5 and wrote, "Sadly, it looks like all the extra budget that went into the Florida episodes and last week's car-studded New Girl crossover has finally dried up, because 'Halloween IV' is strictly limited to the walls of the precinct, a small canvas for what's supposed to be an elaborate series of tricks."[5]

Alan Sepinwall of HitFix wrote, "Still, 'Halloween IV' had its comic moments: the guys' increasingly loud announcements after Amy tried to do a quiet one for Scully's sake, Holt's weird pronunciation of 'kaboodle,' Jake's growing unease around the creepy Boyle body double, to name a few. And even if a part of me is annoyed that the game is now open to all the characters, hearing Gina give her big victory speech with a pronounced lisp due to her missing front teeth was fun."[6] Andy Crump of Paste gave the episode a 8.8 and wrote, "It's one thing to be obvious. It's another thing to be boring. If there's a single word that we can use to describe Brooklyn Nine-Nine's fourth season, it's 'predictable,' and anybody who keeps up with Paste's weekly recaps probably saw this one coming from a mile away. Let's get more specific than that, though, because the same applies precisely to Brooklyn Nine-Nine's annual Halloween antics, too: Every year since the show's first season, the precinct's ongoing contest to crown the ultimate detective/genius telegraphs its outcome more and more, sapping the thrill of good old fashioned guesswork from both the contest and the episodes staged around it."[7]