Valve Software is appealing a recent ruling by Australia's Office of Film and Literature Classification, which denied the zombie-slaying game Left 4 Dead 2 a content rating, effectively banning the title.

Australia's OFLC refused to rate the game on September 17, citing "strong violence." Left 4 Dead 2 is due to release on November 17 on Xbox 360 and PC. It has completed ratings in all other regions, except for Australia, where it was denied a rating, and in New Zealand and the UK, where it is under review.

Valve said it appealed the OFLC rating on September 23. The rating board's report read, "The interactive nature of the game increases the overall impact of the frequent and intense depictions of violence. This, coupled with the graphic depictions of blood and gore, combine to create a playing impact which is high."

In Australia, there is no category for mature content akin to the U.S.-based Entertainment Software Rating Board's "Mature" rating, which means the game's content is appropriate for people 17 years of age and older. Games that fall into this classification are often denied rating in Australia.

In 2008, Australia's classification board refused to rate numerous titles including Shellshock 2: Blood Trails, Dark Sector, Fallout 3 and Silent Hill: Homecoming. All of these games received edits so that they could fall under the MA15+ rating.

In other regions, including Japan, Europe, Korea, and South Africa, the Left 4 Dead 2 was rated for players who are over 17 or 18 years of age.