I will read it too after I finish the game. But the speed runs I saw in other games used game breaking bugs or out of bounds game play to skip areas.
But it could be as simple as an how you play an NPC's story-they would affect the main story and shorten the game to one of the many endings.
Reminds me of the old pick a path adventure books. "What do you do go right or left? I go right. A bugbear jumps out of the shadows and kills your character." Game over you died. LOL