The short opens with a special 51½ Anniversary Celebration of Bugs Bunny. Once that is finished, what happened earlier that day is shown, with a backstage look at Bugs, Daffy, Yosemite Sam, and Elmer Fudd (featuring 3D rendering of the scenery). They attempt a performance, which results in a series of animated "bloopers."
Bugs Bunny begins to dance, but the music is slightly out of tune and skips like a broken record. He then dryly looks at the camera and says his trademark phrase, "What's up, Doc?".
The director and producers laugh as Bugs walks off stage. He then peeks back in to say "Monotonous, isn't it?", which gets the director and producers saying "CUT!" while a bleep plays after he is swiped.
Bugs stops the music midway through dancing, as a result of noticing a loose floorboard on the stage. He then suggests moving the action back and readjusting the camera.
Bugs comes out of the curtain, but he is distracted when the cane flys out after the music stops; otherwise, he failed to catch it.
The cane is thrown before Bugs is ready to catch it, much to his annoyance.
After Bugs enters the stage, he is distracted by the cane & loses it, in which Daffy Duck refuses to throw it to him.
According to Daffy, his contract says that he is not supposed to throw canes to rabbits, resulting in the director reluctantly agreeing to have someone else throw it in Daffy's place.
Daffy enters the stage at the exact time that Bugs does, claiming that he thought that it was the best improvement as he walks away, only to bump his head on the boom mike.
Daffy does not come on stage when he is supposed to. While Bugs, the director, and the producers wait, Daffy is heard telling them to wait, followed by the sound of a toilet flushing. As Daffy then rushes onto the stage, the director can be heard yelling "Cut! CUT! CUT!!"
Elmer Fudd fires a real gun as opposed to a prop. Bugs scolds him, but Elmer responds that he thought that it would be "a gweat, big birthday surpwise" if he finally shot Bugs "after 51½ years of twying." Daffy starts yelling at Elmer for not using the prop gun and neglects Bugs's insistence on cutting. He then walks away as he tells Elmer to expect his lawyers to call him and gets struck in the face by the loose board Bugs had noticed by accident, with the board going through his beak. When Bugs asks if they can cut now,
Daffy says, "You smug son of a--" and is then cut off.
Daffy dances onto the stage with the board still smashed into his face. When he pulls it off, he yanks his beak off as well in the process, but continues speaking, failing to notice it.
Everything plays out correctly until Yosemite Sam emerges from the cake frowning. The director instructs him to act cheerful for the next take. He then goes back into the cake mumbling "But I hates rabbits."
The spectacular performance is done perfectly, except for one thing, as Bugs puts it - there were supposed to be five rockets. A fifth rocket attached to Sam's belt sends him flying about before crashing into the camera. He then yells at Bugs, calling him a "low down flop-eared son of a kangaroo", along with his usual cursing (which lasts throughout the credits) before being knocked-out by an unseen glass object. Bugs then suggests that what had just happened be taken out in the editing before one of the producers asks "Can we go to lunch now?"
(Blooper) Bunny was produced at a time when newer Looney Tunes shorts were being released to introduce the Warner cartoon characters to a younger, more modern generation — a process that was, thanks to the tepid reception of 2003's Looney Tunes: Back in Action, eventually discontinued for some time from 2004 to 2009. The film was animated using a combination of both new computer technology and traditional cells — a first for a Warner Bros. cartoon — with three-dimensional rendering distorting the background in the "backstage" scenes to give the appearance of a handicam being used. The first "backstage" scene in the film, a sequence that goes on for nearly a minute and a half without a cut, is, according to co-director Greg Ford, one of the single longest uninterrupted shots ever attempted in animated cartoons.
The short features several direct references to some of the previous output of Warner Bros. animation department. During the first, aforementioned "backstage" scene, the name of Bosko, the first true Looney Tunes star, can be seen on one of the dressing room doors for a few frames. Midway through the film, there is also a deliberate homage to the "Hunting Trilogy" made popular by Chuck Jones, of whom Ford reportedly holds great admiration. Additionally, during the end credits, the theme song of One Froggy Evening, another Chuck Jones creation, can be heard.
Suppression, rediscovery, and subsequent reputation
(Blooper) Bunny is a self-parody of some of the specials produced for Bugs Bunny's 50th anniversary the previous year, 1990. The short, however, never received its intended theatrical release and was shelved for several years. Albeit "one of the things the studio apparently disliked was the sound of a toilet flushing", critics speculate the true reason for the film's initial suppression was Daffy's rant towards the beginning of the cartoon, in which he is overheard lamenting his role and complaining that "Warner Bros. doesn't have an original bone in its [body]", while making a backward crack at Disney by claiming: "The next thing you know they'll stick me with three snot-nosed nephews" (a la Donald Duck). Jonathan Rosenbaum, in a review for Chicago Reader, noted: "Ironically, Invasion of the Bunny Snatchers, another Bugs Bunny cartoon directed at the same time by the same rebellious duo, Greg Ford and Terry Lennon, is even more directly critical of studio greed, yet it got a pass and wound up on the TV special Bugs Bunny's Creature Features, perhaps because it was less formally transgressive."
(Blooper) Bunny would not receive a television premiere until 1997, after Cartoon Network discovered the film sitting unseen in the vaults. During the years since its rediscovery, the cartoon has garnered a tremendous cult following among animation fans because of its edgy humor, Chicago Reader and is featured on the Looney Tunes Golden Collection: Volume 1, along with an optional audio commentary by co-director Greg Ford.
Jules Faber, in a review for DVD.net, lauded the cartoon as a "highlight" and elaborated further: "Blooper Bunny: Bugs Bunny’s 51½ Anniversary is a clever little blooper reel created in 1991 and utilising some brilliantly conceived early 3D rendering making a very funny behind the scenes mockumentary." Chicago Reader also gave the film a positive mention, saying:
Much of what's funny about Blooper Bunny is the temperament of the aging cast: Bugs rehearsing his opening line, "Gosh, I'm so unimportant," over and over; Elmer still trying to grow hair with tonic; Daffy insanely jealous about being upstaged and threatening to have "my people" talk to "your people"; and Sam grouchily declaring as he's being forklifted onstage that he couldn't care less how old Bugs is — he still hates rabbits.
Dawn Taylor, in a review for The DVD Journal, said: "it has some very funny moments, and falls completely flat in others."
When shown on Kids' WB!, the part where Daffy says, "You smug son of a --" before getting cut off (during the dance takes) was edited down to "You smug --" (due to kids not knowing he said the B word) . Also cut was the end with Yosemite Sam ranting over the end credits and Bugs stating that everything that happened in the cartoon will be fixed in editing 
Written by: Ronnie Scheib, Greg Ford, Terry Lennon