Hearing about video games getting censored in Japan always comes as a shock, considering some of the crazier subcultures and media content. While Dead Space is one of the more well-known games to receive Nipponese censorship, it's also a Western game, and we could have cited cultural nuances as the reason.
But now we have No More Heroes: Heroes' Paradise, the HD console version of No More Heroes for the Wii. Seems it's been confirmed that the uncensored version will only appear on Xbox 360, evidenced by the Japanese rating for the two console editions. A screenshot (above) of the official site shows that the PlayStation 3 version has received a "CERO D" rating, while a a "CERO Z" (kind of like Japan's AO rating) marks the other.
The recent North American trailer also has more blood than the European and Japanese version, as seen below. Be warned, the trailer assumes you've played and beaten No More Heroes Wii, so mind the spoilers.