Storytelling games are a form of competitive storytelling framed in the context of gameplay. However, most existing storytelling games emphasize competitive gameplay and winning at the expense of competitive narrative play; they tend to be storytelling games rather than storytelling games. This paper explores issues related to the design of storytelling games that are won through narrative play and proposes a number of design rules for this. These design rules not only help in the design of storytelling games with a stronger element of narrative play, they also have implications for the design of computational storytelling systems. Key words: storytelling games, interactive storytelling, cooperative storytelling