A judge accepted the British Board of Film Classification's argument that the game had been approved for release on a misinterpretation of the law.
The game was banned in June but the Video Appeals Committee said the game could be classified and released.
The BBFC said that the VAC had been guilty of "a very serious misdirection of law" on the question of harm.
The judge said: "I have taken into account the high public interest in the possibility of harm to children."
Mr Justice Wyn Williams ruled the Board had an arguable case that should go to a full hearing.
Both sides agreed that the game was not suitable for children, but the BBFC argued that if given a certificate for release, it could still end up in the hands of minors.
The judge also suspended the VAC's decision that the game should be classified, halting any possibility of it going on sale until after the High Court challenge, due to take place before 31 January next year.
The BBFC said it would pay any damages that developer Rockstar might suffer as a result of the stay, if the Board loses its legal challenge.
The Board had warned that if the VAC decision had stood, it would have fundamental implications for all of its decisions, including those about unacceptable levels of violence.
Rockstar Games said that Manhunt 2 was "well within the bounds established by other 18+ rated entertainment".