Here is a documentary whose title contains radioactive levels of irony: happiness and joy are very far from what is to be found within. It is a behind-the-scenes profile of the pioneering TV animation Ren and Stimpy, which for those not around in the early 90s, featured an angry chihuahua (Ren) and a dopey, good-natured cat (Stimpy); with its hyper-stylised visuals, bad-taste humour and eye-watering violence, it found a cult status as a mould-breaking kidult show – very much at the adult end of the scale.

The film is built around a profile of John Kricfalusi, Ren and Stimpy’s creator and mastermind; presumably it started out as a warts-and-all account of Kricfalusi’s eccentric (to say the least) management style, which culminated in his firing by Nickelodeon in 1992, shortly after the show’s second season began. However, whatever intentions directors Ron Cicero and Kimo Easterwood may have had were upended by the emergence of even more serious accusations: claims of grooming and underage sex, for which he subsequently apologised. Faced with scrapping everything and starting again, Cicero and Easterwood have folded the material into the litany of alleged abusive behaviour in his studio: initially tolerated as mad-genius enthusiasm but evolving into nasty control-freakery. Kricfalusi is interviewed at length (he apparently agreed only after his victims went to the media), as is Robin Byrd, one of his principal accusers.

The result makes for an unbalanced final film; even if Kricfalusi emerges as a thoroughly unpleasant, if damaged, character, giving him the room to apologise (again) for sexual abuse has the effect of suggesting that somehow that’s the end of it, and even that it was the result of aberrations triggered by workplace stress. Happy Happy Joy Joy is a dismal coda to a fondly remembered show, with Kricfalusi’s collaborators still distressed over what happened. As one of his co-workers put it: “No one else worked harder to fuck it up than this guy.”

• Happy Happy Joy Joy: The Ren and Stimpy Story is available on 16 April on True Story.