As yet, you have a setting, but no story.
A story can be thought of as something intruding into the live of a person and forcing that person to act. The change brought about by the intrusion generates a goal in the protagonist, and the story tells how he works towards and reaches that goal – or fails.
A story can have one or more protagonists, but it must have one. The protagonist is who the reader cares about and whose success or failure he takes interest in. Without a protagonist, there is no story, only description.
A novel may have several protagonists all partaking in the same story, or it may have several unrelated storylines. If you write your story as the story of the Game and all participants are protagonists of the story of the game, or if you write your story as different people experiencing completely unrelated things in the context of that game, is up to you, but you need to come up with either a single story with multiple protagonists, or an individual story for each of your protagonists.
So ask yourself:
What is the story about? It is not about a game. It is about the goals of the participants, the reasons behind those goals, what they have to give up or how they have to change to achieve those goals, and how they fail or succeed.