Not a strange question at all! Let me try to answer it.
The jam states that it accepts story-focused games. Therefore:
- A text-written story without pictures is fine for the jam if it is an interactive fiction (IF) game.
- A book (such as a txt or pdf file) would not fit with the jam's guidelines, as it's not a game. It's a book.
- A (txt or pdf) playbook for a role-playing game (RPG) that is story-heavy would be okay for the jam, as it's a story-focused game.
- A linear (no interactive choices) visual novel (VN) would be accepted in the jam. VNs are made using a game engine.
I hope these examples answer your question.