In Mini Metro, you take on the task of designing the subway layout for a rapidly expanding city. Your city starts with three stations. Draw routes between these stations to connect them with subway lines. Commuters travel along your lines to get around the city as fast as they can. Each station can only hold a handful of waiting commuters so your subway network will need to be well-designed to avoid delays.
Eventually your network will fail. Stations will open too quickly. Commuters will crowd the platforms. How long the city keeps moving is up to you.