Next to having pre-order numbers that were “four times” that of the first game, Left 4 Dead 2 has so far outsold its year-old predecessor by more than two-to-one, Valve says, with last week’s stronger than expected Black Friday sales being a contributing factor to the over 2 million retail copies the perfected zombie apocalypse has sold through. In the two weeks following the game’s November 17 launch, the game’s been played by over one million Xbox Live Gold membership holders, Valve’s VP of marketing Doug Lombardi says, and promises news of the first downloadable content to arrive “very soon.”