Cities: Skylines

Lore & Background

Cities: Skylines is a progression from Colossal Order's previous Cities in Motion titles, which focused on designing transportation systems. Colossal felt they had the technical expertise to expand into a full city simulation, but publisher Paradox Interactive initially hesitated due to the market dominance of the SimCity series. After the critical failure of the 2013 SimCity game, Paradox saw an opportunity and greenlit development. Colossal's goal was to create a game engine capable of simulating the daily routines of nearly a million unique citizens, presenting problems like traffic congestion in a simple, understandable way.

The game starts the player with a 2-by-2-kilometre plot of land, a highway interchange, water access, and starting funds. Players add roads, zones, and basic services to attract residents. As the city grows, new improvements unlock, including schools, fire stations, police, healthcare, waste management, taxes, edicts, and mass transit. Players can designate districts with specific regulations. Buildings have development levels improved by local conditions. Players can purchase up to eight additional land parcels out of 25 within a 10-by-10-kilometre area, though mods can unlock the entire 81-tile map.

The game features a robust transportation system based on Cities in Motion, with roads of varying widths and types, and public transit options like buses, taxis, trams, trains, ferries, and metro systems. Modding is supported via Steam Workshop, with user-generated content and a map editor. Pre-packaged mods include bypassing the unlock system, unlimited funds, and higher difficulty.

Reader's Guide

Cities: Skylines is significant as a city-building simulation that successfully challenged the SimCity franchise after the 2013 SimCity's critical failure. Its development by Colossal Order, a thirteen-person studio, built on their expertise from the Cities in Motion series, using the Unity game engine. The game's core innovation was simulating up to a million unique citizens with realistic traffic behavior, where growth and success were tied to road system design. The traffic simulation used a complex system of fastest-route determination and seven rules for driver behavior, with teleportation back to origin if routes changed mid-transit. The game's commercial success is evidenced by over twelve million copies sold across all platforms as of June 2022. Its legacy includes continued updates as of August 2026, a sequel released in October 2023, and a robust modding community that expanded the game's map size beyond the standard 25 tiles. The game received favorable reviews from critics and established a competing franchise in the city-building genre.

Did You Know?

• The game was developed by a thirteen-person studio at the time of release.
• The game can simulate up to nearly a million unique citizens with daily routines.
• Players can unlock up to 25 tiles of building area, but mods allow access to the entire 81-tile map (324 square kilometres).
• The game's traffic system uses seven rules to regulate simulated driver behavior, with some rules skipped in areas the player is not viewing.

From Bus Routes to Metropolis: The Studio's Leap

Colossal Order was a thirteen-person Finnish studio that had carved out a niche with the Cities in Motion series, games centered on designing efficient transit networks within already-built cities. The team felt they had accumulated enough technical know-how to tackle something far more ambitious: a full-fledged city simulation rivaling the long-running SimCity franchise. Their publisher, Paradox Interactive, was initially reluctant to green-light the project, worried that the SimCity brand still dominated the market and that a new entrant would struggle to gain traction. That calculus shifted dramatically after the 2013 SimCity release collapsed under a wave of critical backlash, opening a window for Paradox to stake a claim in the genre. Colossal set an audacious internal target for the new engine: faithfully simulate the daily routines of close to a million individual citizens while keeping the on-screen presentation intuitive enough that a player could quickly diagnose why a district was failing or a highway was gridlocked. The result, released in March 2015, proved that a small studio could compete with decades of genre incumbents.

Zoning, Tiers, and the Growing Canvas

Every playthrough begins on a modest two-by-two-kilometre parcel, complete with a highway interchange, a stretch of water, and a starting budget. The player's first task is to lay down roads, paint in residential, industrial, and commercial zones, and connect utilities like power, water, and sewage so that residents will settle and workers will show up for jobs. As the population crosses predefined thresholds, the game progressively unlocks deeper layers of governance: schools, fire and police stations, hospitals, waste-management infrastructure, tax edicts, and mass-transit networks. The district system lets the player carve out sub-regions with bespoke rules—restricting which industrial sectors may operate, offering free local transit to cut congestion, adjusting tax rates per development class, or, with the Green Cities expansion, discouraging fossil-fuel vehicles while welcoming electric ones. Buildings themselves climb through development levels as their surroundings improve; a shop near a well-educated neighbourhood, for instance, hires more staff and generates greater tax revenue. Once the player has saved enough, they can purchase adjacent parcels, expanding the buildable area up to eight additional tiles within a ten-by-ten-kilometre region. The hard cap at twenty-five tiles exists to keep the simulation runnable on a wide range of hardware, though community mods can lift the restriction to the full eighty-one-tile map.

A Transportation DNA and a Million Commuters

The game's deepest roots trace back to the Cities in Motion series, and that heritage shows in the remarkably detailed transportation layer. Players can build roads in straight lines or free-form curves, and the zoning grid adapts to whatever shape the adjacent streets take, so cities are never forced into a rigid square layout. Road widths scale from narrow local streets up to major freeways, and variant road types—tree-lined avenues, highways fitted with sound barriers—trade higher construction costs for reduced noise pollution or boosted surrounding property values. On top of the road network, the player can layer buses, taxis, trams, trains, ferries, and metro lines, all designed to pull commuters off congested streets and generate transit revenue. Under the hood, Colossal Order's engine was built with the explicit ambition of simulating the daily routines of nearly a million unique citizens, producing realistic traffic congestion and, crucially, the cascading effects that congestion has on city services and neighbourhood livability. The design philosophy was to surface all of that complexity in a way a player could read at a glance, spotting a failing district or a bottleneck without wading through spreadsheets.

Twelve Million Cities and Counting

Cities: Skylines launched on March 10, 2015, for Windows, macOS, and Linux, and was met with favourable critical reception and strong sales. By June 2022, more than twelve million copies had been sold across all platforms. The game's reach expanded steadily: Tantalus Media handled console ports for Xbox One and PlayStation 4 in 2017, the Nintendo Switch in September 2018, and Google Stadia in May 2022, followed by a remastered edition for PlayStation 5 and Xbox Series X/S in February 2023. From the outset, Colossal Order treated user-generated content as a first-class design goal rather than an afterthought. The Steam Workshop lets players share custom buildings, vehicles, and gameplay-altering mods; pre-packaged mods include tools to bypass the population-tier unlock system, grant unlimited funds, or raise the difficulty ceiling. The game also ships with several pre-made terrains and a built-in map editor that supports real-world geographic features, inviting players to recreate their own hometowns. Since release, a steady stream of expansions and DLC has broadened the sandbox, and as of August 2026 the original title continues to receive updates. A sequel, Cities: Skylines II, arrived in October 2023 to mixed reviews, but the first game's community and content pipeline remain active.