British regulators on Monday banned a toned-down version of the violent video game “Manhunt 2,” saying the changes didn’t go far enough to alter the game’s “bleakness and callousness of tone.” The game’s maker called the decision “a setback for video games.” In June, Take-Two Interactive suspended plans to distribute the game — because it was rejected by the Entertainment Software Rating Board in the United States and by regulators in Europe — but finally agreed, two months later, to release the revised version.