Sega and Platinum Games' violent stylized action game Madworld sold 66,000 units in the U.S. following its March 10th debut, NPD Group told Gamasutra.
Sales performance for the Wii-exclusive was modest, increasingly typical for Mature-rated games (ages 17 and up) that appear on Nintendo's generally family-friendly console.
Madworld's gameplay is purposely over-the-top, with vibrant red blood splattering across a virtually all black-and-white environment, complete with cursing -- a far cry content-wise from top-selling Wii software such as Wii Fit and Mario Kart.
Madworld has been well-received by game reviewers, earning an average score of 82 percent on Metacritic.
In February, Sega's other gory M-rated Wii game, the light gun shooter House of the Dead: Overkill, sold 45,000 units in its debut month in the U.S., according to NPD.
While its recent M-rated Wii games aren't lighting up charts in blockbuster fashion, Sega of America marketing exec Sean Ratcliffe claimed in a recent VentureBeat interview that "House of the Dead has done very well and has absolutely met our expectations. The first set of data for Madworld is very encouraging, as well."
NPD also confirmed to Gamasutra that the M-rated Take-Two and Rockstar Games DS title Grand Theft Auto: Chinatown Warssold just 89,000 units in its opening month of March.
M-rated software on current Nintendo platforms is uncommon. The Entertainment Software Rating Board lists just seven M-rated DS games, including GTA: Chinatown Wars, out of over 1,000 DS titles listed. The Wii has 26 M-rated games out of nearly 1,000 listed on ESRB's website.