Gabe Newell has revealed that Valve was toying around with a "flying fairy game" before it began work on Left 4 Dead.
After marketing director Doug Lombardi admitted to "a few failed starts to build Left 4 Dead" in an interview with PC Gamer, Newell joked: "Well, there was the flying fairy game. Is that the one you were referring to?"
Describing it as "a useful failure", he said it made the Half-Life studio reconsider what it was actually good at making.
"It was so bad," he said, "you wanted to ask yourself: 'How could we make a game that was this bad? And how should we make a game?'
Apparently the unnamed flying fairy game was "this action fantasy sort of role-playing game that had no story".
"And then we said 'OK, that's so horribly wrong. What we should focus in on is AI and playing in co-op, and that's the interesting opportunity.' That was where Left 4 Dead came from."
The rest is history. Excellent history.