Left 4 Dead 1 and 2 have combined for over 12m lifetime sales, according to Valve writer Chet Faliszek.
Faliszek revealed the figure to VG247, as well as speaking on the company's PR approach, which consists of them pretty much shutting up and letting their products do the talking.
“We just let the game speak for itself because the internet has made this thing where, you can’t pull the wool over people’s eyes any more” he said. “They’re going to know you’re hyping. But when a game does really well at pre-release, they’re going to know that you’re not just talking a bunch of PR crap.
“I mean, the Left 4 Dead series has now sold over 12 million copies. That’s amazingly cool, and that wasn’t because I was out there like, ‘Oh my god! This game is amazing! Buy it!’”
Faliszek also confirmed the likelihood we'll see a L4D3 sometime in the future to Eurogamer.
“A 3? You know, some time down the road. Like anything, I would say that to all of our games. So that’s not a promise of when or where. I really love working on that series. It’s one of my favourite series. It’s just so much fun with the characters and the world. I love zombies and I love horror. So, yeah.”