Marc Laidlaw, Valve's former head writer, has shared the story of what it was like pulling together the story threads of the first Half-Life game back in 1997 and 1998. Laidlaw joined the company while it was thick in the development of its seminal shooter and was a key part in turning those early drafts into the game we know today.
I highly recommend reading his full post, as it covers how he got into games writing and landing that job at Valve off the back of an article he wrote about id, the makers of Doom, for Wired. It also goes into a number of different points in the game that were real challenges for the developers, parts of the game that now stand out as Half-Life's strongest moments, like the sequence in the test chamber. But the most interesting part, for me, was how hard Valve had to work to make the entire game a coherent whole.
"At Thanksgiving, just when we should have been bashing open headcrab pinatas, we took a crowbar to the game itself," Laidlaw writes. "The floor of the office was strewn with Half-Life components. We tore the game to pieces, trying to determine what worked, what might work someday, and what would probably never work given what we knew about our abilities. It was in some ways an extremely painful process—both because we knew that the game was going to slip far longer than anyone liked, and because it meant that a great deal of work was going to be lost and probably never seen again."
The whole game was redesigned in this paper stage. Whole parts of the game where carved up and thrown away. It was also a time when designers stepped away from the niche corner of the game they had been focused on and began to look at each other's work. "Each designer has his own talents and interests," Laidlaw recalls. "Wherever possible, the game benefited from matching the designer’s strengths to the needs of the game. We have designers who excel at the broad plan, laying out huge complex areas in a few breathtaking strokes; and others who really go into high gear once the architecture has solidified, and they are able to set up finely balanced dramatic situations using monsters and triggers and scripted sequences. Half-Life benefited immensely when we recognized and reorganized the workflow to take these differences into account. In the last few months of content creation, very few designers were solely responsible for maps they had originated."
Another method for sharing the team's knowledge of the game and to get everyone on the same page was through regular, company-wide meetings where Laidlaw "would tell the entire story of the game as we understood it from beginning to end, so that everyone would be on the same page as we went forward." Laidlaw admits, through that "invariably, as soon as those meetings were over, we’d find some reason to change the story yet again. We’d discard the ending, we’d eliminate a central element, or introduce a new one. It became impossible to keep everyone continually informed on the state of the story."
It's fascinating to get a glimpse inside Valve, such a secretive studio, going through the same pains and stresses of revision that I've heard developers from so many other developers describe. Half-Life didn't drop out fully formed, it was carved into the shape of the game we knew today.