The board believes that there is "insufficient delineation between the depiction of general zombie figures and the human figures." The inability to clearly distinguish the humans from the "clearly fictional 'infected'" was a "major consideration" of the board.
The unedited version of Left 4 Dead 2 is classified RC (refused classification) and "cannot be sold, hired, advertised or demonstrated in Australia." Sorry, mates. An edited version of the game has been approved by the OFLC for consumption in Australia -- censoring "decapitation, dismemberment, wound detail or piles of dead bodies lying about the environment."