Branching narrative
Also said as Branching story, Choose your own adventure, Time cave
The story splits at each choice into separately written paths. Pure branching never rejoins, so every decision really does send you somewhere else.
Nothing else makes a choice feel so large, or makes so much of your writing invisible. Most of what you write, most players never read.
Say it
“Use real branching only for the Act 1 choice. It leads to two separate second acts, about 40 scenes each, and both rejoin before the finale.”
Where you’ve seen it
The Witcher 2 splits on one decision: side with Roche or with Iorveth, and the entire second act plays out somewhere else, with different people and quests. You have to replay the game to see the other half.
Not to be confused with foldback
A branch stays split. A foldback rejoins. Real games mix them, because pure branching gets too expensive within a few choices.