Valve tried to get the board to reconsider while at the same time getting them to approve a censored version of the game that will now be sold in Australia under their MA 15+ rating. However, the original version, according to the board, has violence that is "high in impact, prolonged, repeated frequently and realistic within the context of the game." The board also felt the game's visuals did not make the distinction wide enough between the human characters and the regular run-of-the-mill zombies. Therefore the original version "could not be accommodated within the MA 15+ classification."
Gallery: Left 4 Dead 2 Screenshots