Left 4 Dead had such a rocky start that Gabe Newell wanted to play Counter-Strike instead

techradar.com:

Left 4 Dead's co-lead, Chet Faliszek, reminisces about the early days of the co-op PvE (player vs. environment) zombie shooter and what it took to finally get it off the ground. 

Over the years, we've been able to slowly find out more about the iconic zombie shooter from Turtle Rock Studios and Valve. For example, we now know that Left 4 Dead first started amidst the production of Counter-Strike: Condition Zero. Thanks to an interview with GameDeveloper, we've also gotten to hear just how rocky the start of development was from the horse's mouth.  

Thanks to Valve's famous flat structure, where any employee can bring attention to a project that interests them, Left 4 Dead's very beginnings were somewhat shaky. In the interview, Faliszek recalls becoming the project lead almost by accident. "'Well, you should just talk to Chet, Chet's kind of the person.' Like, no one ever told me I'm running [the game]!" Faliszek said. 

The chaos ensued from there, with Left 4 Dead initially going down a PvP (player vs player) route with four survivors battling against four infected in an abandoned apocalyptic city. While this would return later in the Versus mode, the initial interactions with the PvP weren't at all positive. 

«Gabe just asked me very seriously, 'Why don't I just play Counter-Strike instead? That's working'», Faliszek said.  «I thought he was joking. Like, ha, ha, ha. But then he made me watch him play it; he made me sit in his office and watch and play it.»

The realization that there were significantly better PvP games available to players, as well as the difficulties of balancing two entirely different classes, the survivors and zombies, is what finally pushed Left 4 Dead into the realm of PvE.

While this was by no means