A few weeks ago, Valve's 2009 zombie shooter, Left 4 Dead 2, was reclassified under Australia's new R18+ rating. Previously, the game had to be censored so it could be sold under MA15+, Australia's then-highest rating for games. Now, due to the reclassification, an uncensored version is available to Australia.
For new players, the transition won't be noticeable, with the uncensored version replacing the censored one on the Australian Steam store completely. For long-time players with censored copies, however, Valve has made available a free patch that can restore the game's missing features. Here's a video from 2009 highlighting what these are:
Left 4 Dead 2 - Uncensored [Steam Store]