Left 4 Dead was so busted at launch that it forced a sequel barely 12 months later: "such a broken thing that nobody wanted to touch it"

gamesradar.com:

The creator of Left 4 Dead says the reason its sequel came around so quickly is that the original game was so broken nobody at Valve wanted to work on it any longer.

In an interview with Game Developer, Valve veteran Chet Faliszek discussed the speedy turnaround between Left 4 Dead, which launched in 2008, and Left 4 Dead 2, a full sequel that arrived barely a year later. According to Faliszek, the reason for the turnaround is that "Left 4 Dead was such a broken thing that nobody wanted to touch it."

Valve had pulled a lot of things together to turn Left 4 Dead into the phenomenon that it became, but even then, Faliszek admits that "I don't think outside people can appreciate how broken the Left 4 Dead engine was but still shipped." Maps would load multiple times, and an attempt to fix that problem would see survivors randomly disappear from the game.

That kind of programming calamity is the main reason why Left 4 Dead 2 was pitched as a full sequel. Left 4 Dead was broken by Faliszek's own admission, but Valve was moving so fast that "if it meant breaking something horrible, where you had to load a map [two] or three times but you could playtest it today, we did it." Eventually, Valve had built up such a hardware debt for itself that it was forced to move on.

"There was no way you were going to support mods for Left 4 Dead in the same we did for Left 4 Dead 2 without a big reset," Faliszek claims. Later in the interview, he praises the "insane" breadth of L4D2's modding community, but says that for that community to have gotten its start, "that had to be on Left 4 Dead 2. Left 4 Dead 1 would not have supported that. It would have been crashy, crashy, crashy."

The behind-the-scenes chaos of game development is no