Censors rejected a new version of computer game Manhunt 2, the predecessor of which inspired the murder of a boy, his parents claim.
Stefan Pakeerah's parents said his killer was inspired by Manhunt
It was banned by censors in June, who said it "constantly encourages visceral killing" and are still not satisfied.
Manhunt 1 was attacked by Stefan Pakeerah's parents, after he was fatally stabbed in Leicester in February 2004.
But police said there was no evidence his killer was inspired by the game.
Manhunt 2 was the first video game in a decade to be refused classification, when it was first considered earlier this year.
Rockstar submitted a revised version but British Board of Film Classification (BBFC) director David Cooke said that "we do not consider that these [changes] go far enough to address our concerns about the original version.
"The impact of the revisions on the bleakness and callousness of tone, or the essential nature of the gameplay, is clearly insufficient.
Changes to Manhunt 2 did not go far enough, said censors
"There has been a reduction in the visual detail in some of the 'execution kills', but in others they retain their original visceral and casually sadistic nature."
Rockstar Games has described the subject matter as "in line with other mainstream entertainment choices for adult consumers".
The game is to be released in modified form in the US in time for Halloween.
Stefan Pakeerah's parents believed their son's killer, 17-year-old Warren LeBlanc, was inspired by the game, although police said there was no evidence that Manhunt had played a part in the murder.