The arcade version was originally extremely graphic and gory. When it was released for the first four home entertainment systems (Super Nintendo, Game Boy, Sega Genesis, and Game Gear), all the elements of gore were removed (blood, fatalities, etc.) so Genesis and Game Gear could receive SEGA's "MA-13" rating and Super Nintendo and Game Boy would fit Nintendo's censorship guidelines (Nintendo had no game rating system and the Entertainment Software Rating Board (ESRB) would only be established two years later). When the blood was removed from the SNES and Game Boy versions, it was replaced with sweat and fatalities for all versions were modified so there was no gore. The Sega versions though had a secret code that could convert the game into an "MA-17" version with all gore intact.