Through an interview conducted by colleagues at VG247, Chet Faliszek, writer of several games by Valve, informs us that the series of Left 4 Dead (at the time consisting of two chapters and considering all platforms) has sold over 12 million copies worldwide: it is a more than excellent, hoping that one day will see the light even a possible third installmentSince Valve has yet to produce any title beyond the devilish number "2".

Faliszek clarified the Valve's marketing policy: let the game itself communicates its contents and its merits, without any special strategies, because now the people of the internet has developed critical skills able to unmask and resize any particular emphasised properly by PR.