The Blood Code

Mortal Kombat's September 1993 console releases — announced as "Mortal Monday" in a simultaneous marketing campaign — were the most anticipated home conversions of the era. The arcade game had generated congressional hearings, newspaper editorials, and parental concern throughout the year; its digitised violence and "fatality" finishing moves had put the games industry on notice that content regulation was coming. Both Nintendo and Sega faced the decision of how to handle the home conversion.

Nintendo of America's guidelines for SNES software prohibited blood, excessive violence, and sexual content. The SNES version of Mortal Kombat, developed by Acclaim, replaced blood with grey "sweat," altered the fatalities to remove decapitation and dismemberment, and converted the "Friendship" fatalities' dancing skeletons into something less macabre. The game was faithful to the arcade in terms of gameplay mechanics but sanitised in terms of the content that had made the arcade game culturally notorious. The SNES version was the more technically accomplished port — it had better character sprites and a more accurate colour palette — but it was not the game that players had lined up at arcades to play.

The Genesis version, also developed by Acclaim, included a blood code: entering A, B, A, C, A, B, B at the options screen (a sequence that spelled ABACABB — a Genesis album title — according to developer Dan Forden, who had a taste for music references) restored the blood and the fatalities to arcade accuracy. The code was widely distributed through gaming magazines within weeks of launch; players who wanted the arcade experience on a home platform had a straightforward means of obtaining it.

Sega used the blood code's existence as a marketing position. Its advertisements — "Mortal Kombat. It's Here. Available on Genesis with the blood" — were directed explicitly at the demographic that had experienced the arcade game and knew what they wanted. The ads did not need to explain what "with the blood" meant; the audience for the campaign had been following the controversy since the congressional hearings. The Genesis version outsold the SNES version by a ratio that various estimates placed between 2:1 and 3:1 in the United States. The content difference, amplified by Sega's marketing, was a genuine driver of the sales disparity.

The controversy over Mortal Kombat's home releases, combined with the violence in Night Trap and other games, provided the congressional pressure that led to the formation of the Entertainment Software Rating Board in September 1994 — one year after Mortal Monday. Senator Joseph Lieberman and Senator Herbert Kohl had threatened federal regulation of game content; the industry's voluntary rating system was the alternative the publishers preferred. The ESRB rating system — with Mature, Teen, Everyone, and Adults Only categories — was in place before Mortal Kombat II's home releases in 1994.

The irony of Mortal Kombat's console controversy is that the game's violence, which seemed extreme in 1993, was less graphic than what console games of the late 1990s would produce with advanced hardware and developer experience in rendering realistic damage. The congressional alarm was calibrated to digitised photographs of actors rather than rendered violence, which the aesthetic distance of polygon graphics would soon render less immediately disturbing to concerned legislators. The ESRB it produced remains the North American game rating system, thirty years after the hearings that created it.