official details regarding Left 4 Dead's "The Sacrifice" DLC lies an announcement: Left 4 Dead 2 will be available on Mac starting Tuesday, October 5. As per usual, Mac users who previously purchased Left 4 Dead 2 on Steam for PC will automatically receive access to the game, along with free downloads of "The Passing," "The Sacrifice" and "No Mercy" add-ons.
In the same note, Valve also apologizes to Left 4 Dead 1 owners -- since the sequel is making it onto Mac before the original. The company states it's "running a little late" and that it hopes to "have it out in time to celebrate Halloween." If you previously purchased L4D on Steam for PC, you'll have access to everything once the Mac version arrives.