A recent question asked for pointers for writing for games, and the gist of the answers was that it's not very unlike writing books. The underlined differences were only superficial. There's a plotline to follow and obstacles to conquer. You write the plot and develop essentials and let the programmers handle dynamics and interactivity.
That might be fine if you work at Valve, writing games that are great fun to go through the first time, a little fun the other time when you discover hidden tastes, and then interesting the third time when you enable the developer commentary. Then there are challenges and multiplayer that make it great arcade fun, but the storytelling part is entirely exhausted.
Now what if I want to write something like Tsukihime? 1
I will not spoil the details of the plotline of Tsukihime, but let me just say it is meant to be played exactly five times, and only on fifth walkthrough you will be able to fully appreciate the depth and hidden meanings of everything recurring throughout your prior walkthroughs. More interestingly, while the first two walkthroughs pretty much follow the same storyline, staying just to two sides of the barricade, starting with the third you open up a wildly straying tangent that completely abandons the first premises.
And this is still fairly linear. What about games like Morrowind, where outside of three entirely different ways of getting the main quest done, you get a wild tangle of intersecting, conflicting, synergizing, complementing or opposing quests for various factions? Three vampire clans at war, join any. Imperial Temple vs Tribunal Temple, distrusting and hostile, join any again. Become a werewolf or fight werewolves.
A book has a progression from beginning to end, a storyLINE. Events follow in logical progression of cause-effect.
How can you write something where you have a storySPAGHETTI to create?
In particular, you have a number of smaller plotlines. Call them quests, questlines or story arcs if you like. How to
- manage their interconnections - hold a tight grip over how they influence (or break!) each other? 2
- handle their prerequisites to avoid both circular dependencies and stupid limitations. 3
- do this all from most mundanely technical viewpoint - How to write down multiple (lengthy) entries that have no apparent order and a wild web of connections, especially keep these connections visible and easily editable, and easy to follow? Keeping tab of limitations and prerequisites for these to be possible? Not getting lost and holding it whole in my head, while the player just holds the current walkthrough?
1 Example chosen as striking the middle ground between linear and convoluted beyond hope, balancing great story with considerable nonlinearity; for the latter example try Kagetsu Tohya, nearly impossible to get through without a guide, and no, I don't think it's a good idea.
2 I will never forgive Oblivion with its four(!) guild questlines, after Mages Guild questline making me the Archmage, to have the Thieves Guild questline have me steal a magic staff from myself to convince myself that I, the Archmage should recall my battlemages to better protect my guild from myself, the thief.
3 I've got a scroll of Raise Dead, I don't get what's so bad about the assassin getting caught after killing the victim!