4X games are a genre of strategy video game in which players control an empire and ‘explore (reveal surrounding territories), expand (create new settlements), exploit (gather resources), and exterminate’ (eliminate rivals). The four elements often overlap with each other and vary in length depending on the game design.
For example, the ‘Space Empires’ series and ‘Galactic Civilizations II’ have lengthy expansion phases, because players must make large investments in research to explore and expand into every area. The term was first coined by video game critic Alan Emrich in his 1993 preview of ‘Master of Orion’ for ‘Computer Gaming World,’ in which he rated the game ‘XXXX’ as a pun on the rating for pornography.
The earliest 4X games borrowed ideas from board games and 1970s text-based computer games, and are noted for their deep, complex gameplay. Emphasis is placed upon economic and technological development, as well as a range of non-military routes to supremacy. Games can take a long time to complete since the amount of micromanagement needed to sustain an empire scales as the empire grows. 4X games are sometimes criticized for becoming tedious for these reasons, and several games have attempted to address these concerns by limiting micromanagement with varying degrees of success. The first 4X games were turn-based, but real-time 4X games are not uncommon. Many 4X games were published in the mid-1990s, but were later outsold by other types of strategy games. ‘Sid Meier’s Civilization’ is an important example from this formative era, and popularized the level of detail that later became a staple of the genre.
While many strategy games arguably contain a similar ‘explore, expand, exploit, exterminate’cycle, game journalists, developers and enthusiasts generally apply ‘4X’ to a more specific class of games, and contrast 4X games with other strategy games such as ‘Command & Conquer.’ Hence, writers have tried to show how 4X games are defined by more than just having each of the four Xs. Gaming sites have stated that 4X games are distinguished by their greater complexity and scale, and their intricate use of diplomacy beyond the standard ‘friend or foe’ seen in other strategy games. Reviewers have also stated that 4X games feature a range of diplomatic options, and that they are well known for their large detailed empires and complex gameplay. In particular, 4X games offer detailed control over an empire’s economy, while other strategy games simplify this in favor of combat-focused gameplay.
4X games are a subgenre of strategy games (a genre which emphasizes skillful thinking and planning to achieve victory), and include both turn-based and real-time strategy titles. The gameplay involves building an empire, which takes place in a setting such as Earth, a fantasy world, or in space. Each player takes control of a different civilization or race with unique characteristics and strengths. Most 4X games represent these racial differences with a collection of economic and military bonuses, although a few games such as ‘Sword of the Stars’ offer widely different abilities to each race. 4X games do not typically feature a campaign or scripted narrative, as this would interfere with the freedom of building a massive empire over multiple hours of gameplay.
4X games typically feature a technology tree, which represents a series of advancements that players can unlock to gain new units, buildings, and other capabilities. Technology trees in 4X games are typically larger than in other strategy games, featuring a larger selection of choices. Empires must generate research resources and invest them in new technology. In 4X games, the main prerequisite for researching an advanced technology is knowledge of earlier technology. This is in contrast to non-4X real-time strategy games, where technological progress is achieved by building structures that grant access to more advanced structures and units. Research is important in 4X games because technological progress is an engine for conquest. Battles are often won by superior military technology or greater numbers, with battle tactics playing a smaller part. In contrast, military upgrades in non-4X games are sometimes small enough that technologically basic units remain important throughout the game.
Combat is an important part of 4X gameplay, because 4X games allow a player to win by exterminating all rival players, or by conquering a threshold amount of the game’s universe. Some 4X games, such as ‘Galactic Civilizations,’ resolve battles automatically, whenever two units from warring sides meet. This is in contrast to other 4X games, such as ‘Master of Orion,’ that allow players to manage battles on a tactical battle screen. In lieu of combat, 4X games allow rival players to engage in diplomacy. While some strategy games may offer shared victory and team play, diplomatic relations tend to be restricted to a binary choice between an ally or enemy. 4X games often allow more complex diplomatic relations between competitors who are not on the same team. Aside from making allies and enemies, players are also able to trade resources and information with rivals.
In addition to victory through conquest, 4X games often offer peaceful victory conditions/goals that involve no extermination of rival players (although war may be still be a necessary by-product of reaching said goal). For example, some 4X games offer victory to a player who achieves a certain score or the highest score after a certain number of turns. Many 4X games award victory to the first player to master an advanced technology, accumulate a large amount of culture, or complete an awe-inspiring achievement. Several 4X games award ‘diplomatic victory’ to anyone who can win an election decided by their rival players, or maintain peace for a specified number of turns.
To experience a detailed model of a large empire, 4X games are designed with a complex set of game rules. For example, the player’s productivity may be limited by pollution. Players may need to balance a budget, such as managing debt, or paying down maintenance costs. 4X games often model political challenges such as civil disorder, or a senate that can oust the player’s political party or force them to make peace. Such complexity requires players to manage a larger amount of information than other strategy games. Game designers often organize empire management into different interface screens and modes, such as a separate screen for diplomacy, managing individual settlements, and managing battle tactics. Sometimes systems are intricate enough to resemble a minigame. This is in contrast to most real-time strategy games; ‘Dune II,’ which arguably established the conventions for the real-time strategy genre, was fundamentally designed to be a ‘flat interface,’ with no additional screens.
Since 4X games involve managing a large, detailed empire, game sessions usually last longer than other strategy games. Game sessions may require several hours of play-time, which can be particularly problematic for multiplayer matches. For example, a small-scale game in ‘Sins of a Solar Empire’ can last for over 12 hours. However, fans of the genre sometimes expect and embrace these long game sessions. Turn-based 4X games typically divide these sessions into hundreds of turns of gameplay.
Because of repetitive actions and long-playing times, 4X games have been criticized for excessive micromanagement. In early stages of a game this is usually not a problem, but later in a game directing an empire’s numerous settlements can demand several minutes to play a single turn. 4X games began to offer AI governors that automate the micromanagement of a colony’s build orders, but players criticized these governors for making bad decisions. In response, developers have tried other approaches to reduce micromanagement, and some approaches have been more well-received than others. Commentators generally agree that ‘Galactic Civilizations’ succeeds, which is attributed to the game’s use of programmable governors. ‘Sins of a Solar Empire’ was designed to reduce the incentives for micromanagement, and reviewers found that the game’s interface made empire management more elegant. On the other hand, ‘Master of Orion III’ reduced micromanagement by limiting complete player control over their empire.
The first 4X are arguably ‘Andromeda Conquest’ and ‘Reach for the Stars,’ which were published in 1983, and are now seen as 4X games in retrospect. Although ‘Andromeda Conquest’ was only a simple game of empire expansion, ‘Reach for the Stars’ introduced the relationship between economic growth, technological progress, and conquest. In 1990, Sid Meier released ‘Civilization’ and popularized the level of detail that has become a staple of the genre. ‘Sid Meier’s Civilization’ was influenced by board games such as ‘Risk’ and the ‘Avalon Hill’ game also called ‘Civilization.’ A notable similarity between the ‘Civilization’ computer game and board game is the importance of diplomacy and technological advancement. Sid Meier’s Civilization was also influenced by personal computer games such as the city management game ‘SimCity’ and the wargame ‘Empire.’
Following the success of ‘Civilization’ and ‘Master of Orion’ (1993), other developers began releasing 4X games. In 1994, Stardock launched its first version of the ‘Galactic Civilizations’ series for, and the long-standing ‘Space Empires’ series began as shareware. ‘Ascendancy’ and ‘Stars!’ were released in 1995, and both continued the genre’s emphasis on strategic depth and empire management. Sid Meier’s team produced ‘Colonization’ in 1994 and ‘Civilization II’ in 1996. By the late 1990s, real-time strategy games began outselling turn-based games. As they surged in popularity, major 4X developers fell into difficulties. Sid Meier’s Firaxis Games released ‘Sid Meier’s Alpha Centauri’ in 1999 to critical acclaim, but the game fell short of commercial expectations. ‘Civilization III’ encountered development problems followed by a rushed release in 2001.
In 2003, Stardock released a remake of ‘Galactic Civilizations.’ In 2004 the Creative Assembly released the critically acclaimed ‘Rome: Total War.’ ‘Civilization IV’ was released at the end of 2005. It is now considered one of the greatest games in history. In 2008, ‘Civilization Revolution’ was released for game consoles. It was followed by ‘Civilization V’ in 2010. Additionally, there is a loyal base of 4X gamers who have supported free software releases such as Freeciv, FreeCol, Freeorion, and partially free C-evo.
Eventually real-time 4X games were released, such as ‘Imperium Galactica’ in 1997 and ‘Starships Unlimited’ in 2001. In 2006, the genre was refreshed by the appearance of ‘Sword of the Stars,’ featuring a combination of a turn based strategy part and real-time tactical combat phase, both in 3D. Sword of the Stars was the first 4X game to offer a physical simulation in battles. The blend of 4X and real-time strategy gameplay led Ironclad Games to market their 2008 release ‘Sins of a Solar Empire’ as a ‘RT4X’ game.
Cross-fertilization between board games and video games continued. For example, some aspects of ‘Master of Orion III’ were drawn from the board game ‘Twilight Imperium.’ Even ‘Sins of a Solar Empire’ was inspired by the idea of adapting the board game ‘Buck Rogers Battle for the 25th Century’ into a real-time video game. Going in the opposite direction, Eagle Games made a board game adaptation of ‘Sid Meier’s Civilization’ in 2002.