I'm no expert, but I'd imagine the story has to be complete before development starts on the game. Maybe something gets tweaked here or there song the way, but I can't see the approach being to write as production goes, or at least not to invent the story as production goes

No, often the story is written close to the end, to tie all the content together. Writers hate it, but it's common.

Seems each have different experiences.

In my experience, the games focus first around the core mechanics, story afterword.  The thing that is fundamentally fun or compelling about the mechanics.

For example, when we had the Hasbro brands opened up to us we were asked to create pitches on many different products.  One line of games focused on the Tonka Truck lineup, where the first thing we did was get a sandbox with assorted toys along with all the trucks to figure out why playing with the things is fun for kids in the first place. The mechanics of building things and destroying things, both individually and with a partner, were fully explored. That line was very nearly greenlit. Another line was Nerf, and we experimented with what was so fun about having blasters and a pile of bullets; it isn't the trigger pulling aspect, but instead the comedy and quirkiness of the guns and darts. The game designs explored mechanics of weighing things down with many heavy darts, striking unexpected targets for odd reactions, massive guns that slowly explode with a truly epic foam dart, and small machine-gun style guns that feel more like firing a squirt gun than a real weapon.  Yet another line was the Littlest PetShop lineup, where we focused on unexpected moments of delight as the fun little animals had social interactions while frolicking in the world.

People will play a fun game even if the story line is stupid.  "I'm a plumber saving a princess while eating mushrooms". Or "Save the world from the Evil Alien/Foreign/Terrorist invaders!". "Pigs stole the eggs!".  

Said differently: People haven't spent all those hours on League of Legends, DotA2, Angry Birds, Smash Bros, Guitar Hero, Tetris, and Minecraft because they had amazing story lines.  

Touche.. But OP asked in the context of "narrative rich" games.  The idea I had in mind was.. Telltale games, or something like "The Last of Us".  I'd imagine the story development process in games like those is more robust, no?

(Admittedly, I'm going off an assumption that could be off-base)

5 hours ago, masskonfuzion said:

Touche.. But OP asked in the context of "narrative rich" games.  The idea I had in mind was.. Telltale games, or something like "The Last of Us".  I'd imagine the story development process in games like those is more robust, no?

The story in The Last Of Us was written by the Creative Director. As the name suggests, they have a lot - probably the most - influence over how a game is made and what goes into it. So they have the luxury of arranging the game somewhat to fit their story. In cases like that, you can see how the story structure is planned in advance, and probably constantly refined as the content is created and feedback from testing comes in.

Nobody will be writing out a complete script before development starts, because too much of the story will depend on technical issues that come up during development. Most likely they start with an outline before development, progress to a treatment during early development, and then write out detailed dialog and shooting script details for cutscenes along the way.

I see, yeah that makes sense.