I'm sure we all could list hundreds of examples where games released in Japan were released in the Western market with edits of various things censored out due to thinking they would be viewed as offensive, immoral, illegal, or what have you. Naked chicks became clothed, religious imagery removed, blood and violence toned down, race or sex of (mostly) enemy characters changed... the list goes on forever. Sometimes you had licensed characters that were reworked to now have generic non-licensed characters (Black Belt/Last Battle versus Fist of the North Star) or licensed characters removed completely (Pepsiman in Fighting Vipers).
Can you think of any games where the reverse is true? I don't mean alterations just for the markets in Australia or Deutschland that would otherwise prevent it from being rated or sold, but rather changes where the Japanese version was censored while the Western release was not? I can only think of two.
Mortal Kombat II (SNES/SFC) - Japanese release has green blood and when you perform fatalities the screen turns black and white.
The House of the Dead (Saturn) - Japanese release only had green blood while the US version had red or green blood with red by default.
Those are really the only two examples of censorship I can think of. Seems like Zombie Revenge had either a code or a hidden violence setting not found in the Japanese original but I may have just dreamt that.