A traffic-management puzzle game in which the player designs the transport network of a growing city. Houses and workplaces appear over time, and the player connects them by drawing roads so that residents can commute. A queue forms at every destination, and a run ends when one of those queues overflows. Each night the city adds new houses and destinations, so the player has to keep extending and reworking the network. As the city grows, more transport options become available: buses, trams, river boats and underground lines. The campaign is set in seven cities: London, Las Vegas, Venice, Rio de Janeiro, Stockholm, Mexico City and San Francisco. Each city has its own geography and its own set of transit modes. Venice has water buses, Las Vegas has an elevated monorail instead of an underground, and Stockholm uses boats instead of trams. Besides the campaign there is a Sandbox mode with no fail state and unlimited resources, and a Custom mode where the player chooses the terrain, the available transit modes and the growth rate.