"How to design mixed-initiative games?"
About
Snake Story explores how human-AI co-creative storytelling can work within a game that has clear gameplay goals, not only writing support. In this project, we designed a mixed-initiative storytelling game that combines the classic Snake mechanic with GPT-3-based co-writing, where players choose AI-generated story segments while managing survival, obstacles, and time pressure. Through a qualitative study with 11 players, we found that people engaged with the experience in different ways, as writers, players, or readers, and that these roles shaped how they balanced story quality against gameplay demands. This work contributes both a novel game prototype and design insights for future AI-supported storytelling games that better integrate play, authorship, and narrative engagement.
Snake Story
In Snake Story, players control a snake on a grid and choose between candies that each correspond to a different AI-generated story segment. Eating a candy adds its associated text to the evolving narrative, but each choice also affects gameplay through benefits or penalties, such as restoring health, adding obstacles, or unlocking a chance to write custom text. Because the snake must keep moving, avoid collisions, and survive long enough to continue the story, the gameplay creates a constant trade-off between building a better narrative and staying alive in the game.
Methods
We used a research-through-design approach to create Snake Story as a playable prototype and examine how mixed-initiative storytelling could work with more prominent game mechanics. To study player interaction, we conducted a qualitative playtest with 11 game design students, in which participants played the game, thought aloud during play, and then completed a semi-structured interview. We analyzed gameplay records, observations, and interview data through open coding to understand players’ strategies, experiences, and perceptions of their roles in the co-creative process.
Results & Insights
The study showed that players experienced Snake Story in three distinct ways: as writers, who focused on crafting a coherent story; as players, who prioritized surviving and winning the game; and as readers, who enjoyed continuing the story through play. These different roles shaped how people balanced narrative quality against gameplay pressure. A key insight from this work is that mixed-initiative storytelling games should not assume all players want the same experience. Instead, designers should align gameplay mechanics with different player motivations, whether that means supporting authorship, emphasizing challenge, or strengthening the link between play and unfolding narrative.