A trove of Counter-Strike maps recently leaked on the internet, including a mod that was the predecessor to the survival co-op game Left 4 Dead. The mod is even fully playable, as long as you know how to set up your own server.
According to gaming leaks streamer Tyler McVicker, the prototype originated as a game mode in Counter-Strike: Condition Zero. Players would assemble in groups of up to four people and play as the terrorists. The goal was to plant a bomb while defending against waves of infinitely respawning hordes of counter-terrorists. These enemies only used melee attacks, which made them the perfect predecessor to L4D zombies.
The developers at Turtle Rock Studios clearly thought that the mode had a lot of potential. They polished it further during the development of Counter-Strike: Source, where it was renamed “Terror Strike.” L4D director and Turtle Rock co-founder Mike Booth confirmed the mod’s existence over Twitter. “It was our lunchtime go-to game,” he wrote. “We wanted Valve to release it but never got traction for some reason.” Turtle Rock was known as “Valve South” after Valve acquired it in 2008. They had already started development on the survival co-op, but they didn’t have an advocate within the parent company.
Former Valve writer Chet Faliszek told Kotaku that Turtle Rock had already started working on L4D before he became involved. The game caught his attention, and he became its “champion.” “I was one of the people who checked it out and told Gabe about it at lunch,” said. “I went on so much about it, he said I should just go work on it.” As a result of his involvement, he was able to increase the scope of its production. Faliszek recruited over a hundred Valve developers for L4D after the company had acquired Turtle Rock.
Valve published the zombie survival co-op in 2008. A sequel followed in the very next year Turtle Rock eventually separated from the publisher and became an independent studio in 2011.
It’s pretty neat that such a prolific game originated as a mod that its creators had been personally passionate about, rather than a carefully planned product. If you want to see what L4D looked like back in its ideation stage, you can download the mod here.