Cities: Skylines is a city-building game developed by Colossal Order and published by Paradox Interactive. The game is a single-player open-ended city-building simulation. Players engage in urban planning by controlling zoning, road placement, taxation, public services, and public transportation of an area. Players work to maintain various elements of the city, including its budget, health, employment, and pollution levels. Players are also able to maintain a city in a sandbox mode, which provides unrestricted creative freedom for the player. Cities: Skylines is a progression of development from Colossal Order's previous Cities in Motion titles, which focused on designing effective transportation systems. While the developers felt they had the technical expertise to expand to a full city simulation game, their publisher Paradox held off on the idea, fearing the market dominance of SimCity. After the critical failure of the 2013 SimCitygame, however, Paradox greenlit the title. The developer's goal was to create a game engine capable of simulating the daily routines of nearly a million unique citizens, while presenting this to the player in a simple way, allowing the player to easily understand various problems in their city's design. This includes realistic traffic congestion, and the effects of congestion on city services and districts. Since the game's release, various expansions and other DLC has been released for the game. The game also has built-in support for user-generated content. The game was first released for the Windows, macOS, and Linux operating systems in March 2015, with ports to the Xbox One and PlayStation 4 game consoles being released in 2017 and for the Nintendo Switch in September 2018 developed by Tantalus Media. The game received favourable reviews from critics, and was a commercial success, with more than five million copies sold on the PC platforms alone as of March 2018. Players start with a plot of land - equivalent to a 2-by-2-kilometre (1.2 mi Ã— 1.2 mi) area along with an interchange exit from a nearby highway, as well as a starting amount of in-game money. The player proceeds to add roads and residential, industrial, and commercial zones and basic services like power, water, and sewage as to encourage residents to move in and supply them with jobs. As the city grows beyond certain population tiers, the player will unlock new city improvements including schools, fire stations, police stations, health care facilities and waste management systems, tax and governing edicts, transit, and other features to manage the city. One such feature enables the player to designate parts of their city as districts. Each district can be configured by the player to restrict the types of developments or enforce specific regulations within the district's bounds, such as only allowing for agricultural industrial sectors, offering free public transportation to residents in the district to reduce traffic, increased tax levels for high commercialized areas, or even with the Green Cities DLC, placing a toll on fossil fuel vehicles entering a district while excluding hybrid and electric vehicles, akin to the London Congestion Charge Cities: Skylines brings back classic management gameplay with an endless sandbox and new ways to expand the city. Aiming at a deep, creative and accessible experience, the game varies in how hard-core it is but will always offer a genuine challenge based on complex and rich systems. Newly optimized for play on a controller, the PlayStation4 Edition brings the creative management game to consoles along with Cities: Skylines -After Dark, the game's nightlife-focused expansion. PlayStation4 players finally have the opportunity to experience the award-winning management game.