4x Design

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Thoughts on game balancing a 4X game

4X - explore, expand, exploit and exterminate, the kind of game Freeciv is.

The growth curvesEdit

Expansion leads to more rapid expansion, and so you get a base curve of growth that is not linear. This is a key challenge. In order to allow other strategies than 'expand expand expand', there must be rewards of equal importance for choosing building in depth.

Master of Orion 2 has an increasing bonus on its buildings as they become more advanced, and it takes a while to get a fully developed planet. A fully developed planet with a good set of random parameters is more important in the game than having lots of small planets are not well developed.

Other games choose to limit player choices dramatically in production places (cities/planets) that are not well developed. This is the road taken by Master of Magic, where new expansions take a long time before become useful.

RTS games often combine choice limits with the limited ability of a player to defend multiple production places. This depends on an attackers ability to mount attacks at any time during the game, and your lack of ability to either predict the opponent's place of attack or move your defensive forces to match the attack in time. In Civ games, distances are so vast and units so slow, that suprise attacks are either uncommon, predictable or easy countered by movable defenses. The first two Civ games had barbarians that would pose some theoretical challenge to outposts, but they were never a real threat, and to the extent that they were, they would pose a threat to any of your cities, and indeed to your entire civilization, which would not be the point here.

  • Previous unbalanced excessive emphasis in eXpansion at the expense of eXploitation has been addressed with unhappiness extensions. Growth curve in eXpansion rate are capped by necessary eXploitation. Players building too many cities too quickly will face population unhappiness requiring cap busting city Building improvement and must find ways to balance the various aspects.

Game challengeEdit

The challenge of the game should follow, as a graph, a horizontal line, not a hilltop curve. Too often the first third of the game is boring and repetitious, the second third of the game decides who wins, and the last third is a mop up operation of an enemy that is guaranteed to lose.

Civ games have traditionally used barbarian uprisings and huts to give the first third of the game variation and challenge. While moderately useful for single player games, it fails for multiplayer games, where fairness does not permit such randomness.

It is important that the player is allowed vital choices in the first third of the game, instead of what is all too common, a short list of choices from which good players always choose the same options. Allowing a player to customize his player type (nation or race), as in Master of Orion 2, makes each game more varied, and in the early game, the results of the choices made in the player type customization are played out.

The last third of the game should either be kept challenging by making available high risk and high gain options for the losing parties, or dropped entirely by forcing surrenders or allowing easy victory when one player becomes so strong that it is unlikely that anyone else will win.

One way to avoid a slow mop up in the last third of the game is simply to give the winning player access to overpowered weapons. Command and Conquer Generals does this with its 'superweapons', which are hard to keep for a failing player, but can be used by a winning player to tear apart the defenses of the failing player in no time and from afar. However, such overpowered weapons should then never be allowed to determine the winner, and need to have the weakness of being easy to destroy or disrupt by the more offensive player.

Typically high risk, high gain options have involved choices that have stunted development. For example, in Civ3 the enemy can sacrifice citizens to conscript new units or go into a government that is better for warfare but very for developing. While good for countering surprise attacks or surprising breakthroughs in your defenses, such moves more often than not merely drag the game out further in time. If all you can do is defend, you eventually will lose. This has been true of almost all 4X games.

When creating a high risk, high gain counterstrategy, make sure it is not a high risk of a long, drawn out game. The risk should be the risk of a quick and decisive defeat. For example, one strategy might be to produce a powerful unit which will lose you the game if it is lost. Another strategy is a unit that is very powerful in certain situations, but hard to use and easily lost; an example of this is the Templar unit in Starcraft. There could be a powerful game tactic that can tip the game in the player's favour, but which depends on the enemy doing something wrong. Again, the Templar unit in Starcraft exploits bad unit management on part of the enemy to do most of its harm. In Civ games this exists to a limited degree in that entire stacks of units can be destroyed at once.

Both winning player and losing player gain something by the availability of such high risk, high gain choices. The winning player may complete the game (with a win) faster and at more challenge and fun. The losing player gets a chance to turn the tide, and instead of just watching his empire predictably getting taken apart bit by bit, gets to go down figthing with high spirits. The game ends with a bang instead of a wimper.

  • It's possible to use Diplomats/Spies to steal technology to narrow technological gap. For high risk/gain strategy, conquering the capital city of the winning player will trigger a civil war in the his/her empire and will generate a new AI to take control of a part of his/her territory. For extremely high risk/gain strategy, triggering global warming with severe amount of pollution (replacing green buildings with non-green alternative) will devastate enemies productive capabilities (and the total amount of units they can actively support).


All options in the game should have their uses. If good players never use them, they should either be upgraded or removed. Having options that are merely newbie traps is not a good idea. This will merely hide an underlying problem which is lack of actually available player strategies. A case in point, in Freeciv 1.14, good players almost never build any buildings in their cities - it is so much better to just make more cities, most buildings could just as well not exist.

The number of viable options should expand during the game, but remain limited so that at no point in the game is the player offered a confusing and unwieldly amount of options to be managed at once. Branching options in such a way that choosing one branch of development shuts off another is one way to manage this problem. Master of Orion 2 does this by only allowing you to research one tech in each tech category. Making some options require others is another way to easily control the number of options available, while not reducing the real strategic choices available much - Civ games use this to some degree, RTS games tend to use it more consistently.

Well-rounded game resources are nearly always superior to specialization. This leads to a dearth of actually playable strategies. In Civ2, the whale map resource has an average amount of all three fundamental income types, and in the absence of the unlikely availability of map resources that have a lot of all of the other three income types, the whale is always better. It is, in fact, so much better that the amount of whales present in your start position can be significant factor in deciding who wins. Well-rounded resources should be in sum be much worse than specialized resources.


For every effective strategy there should be an effective counter-strategy. There should never be a situation where you can see the enemy's strategy a good time in advance, but you are unable to exploit this knowledge to your advantage.

If you know what the enemy is doing and have equal skill, you should always win.

In Starcraft, if the enemy builds up Zealots to attack, you can build Firebats to defend, and the Zealots will be toast. Build only Firebats and he has Dragoons instead, and you are toast.

In Civ games (and here I include the Master of X series) less advanced units are totally inferior to more advanced units, to the point where a player who lags in tech development is essentially defenseless against a more advanced player. Pikemen cannot do much against attacking Armor. This is largely unavoidable for this kind of game, where development plays such a vital role.

The most important rule to make effective counter strategies possible is that all units must be specialized, and all units must have at least one weakness. Again, well-roundedness is the death of good game balance.

In RTS games, weaknesses are often expressed in terms of size and type of attack. Small units are easily destroyed by 'splash' area attacks, while large units are not as vulnerable to such attacks but instead fall victim to other attack types. In Dune 2, there were two basic attack types and weakness types, the machine gun (against small targets) and rockets (against large targets).

In Civ 2, this kind of rock-paper-scissors thinking was attempted with the Pikemen and horse units duo. However, it was not much successul, because there was not sufficient motivation not to build pikemen once they were available, and the advantages of horse units were not sufficiently reduced by Pikemen. For this to be a strategy, instead of merely a flavour, the Pikemen unit must have a significant weakness that the Phalanx does not have, and the horse units that attack must be significantly disadvantaged.

  • The ridiculous defense bonuses in FreeCiv allows Elite Musketeer fortifying behind City Walls on top of the Hill terrain to defend against almost all land units (except Howitzer which ignore some defense bonuses). Engineers can raise the city by altering the terrain into Hills to boost city defenses late in the game to compensate for technology gap. Raising the city and surrounding land into hills also protect the city from effects of climate change should enemies decide to use planet killing strategy. 4X games is not the same as RTS games and part of the difficulty is in figuring out how much resource to divert away from the current war into technological research in preparation for future wars, whereas tactics and unit diversity is minimized in 4X games.

Micromanagement - moving entities aroundEdit

In 4X games, it is the rule that they start small where turns fly by quickly, and end up really big where turns take almost forever to get done. This is partly due to expansion, as described above, but also that production usually increases much faster than factor costs. So while in early wars you could have a dozen units attacking on each side, when you get in the late game, each side has many dozen units hoarded up. This is in itself not a bad thing, but it must be considered very carefully. Some increase in sheer numbers is a good thing to show the player a clear sign of progress, but having to command an unwieldly number of units is not a good thing.

The obvious solution if you see that the game gives too many entities to manage in the late game is to increase costs, and make up for it by making each game entity much better. In Freeciv a musketeer that is fortified on a hill can defeat an Armor unit. So the high tech player usually sends in a lot of armor to defeat an inferior opponent. Usually the technologically superior player also has numerical superiority as well. This could be changed. The technologically inferior opponent could have more units, not less, since his units could be cheaper to build and upkeep, while the technologically superior player could have fewer units, not more.

  • Rules could be recoded so that Ancient/Medieval units costs 1 production point to maintain, Gunpowder/Industrial units costs 2 production points to maintain, and Modern/HiTech units costs 3 production points to maintain. This shouldn't be too hard to do.

Micromanagement - productionEdit

As the game gets into the later part you get a lot of production bases (in Freeciv, cities). Each of these needs to be controlled, and the control mechanism that was designed for the early game usually starts to show its deficiencies.

The game fun can be seen as a balance between chore tasks and novelties. You do the chore tasks (moving units, placing citizens, etc) in order to achieve novelties (new achievements in the game). If the ratio of chore tasks to novelties becomes too high, the game becomes boring to an overwhelming number of the players. Each game entity has some chore tasks associated with it - moving, placing, etc.. As the number of game entities grow, the amount of chore tasks grows too. If the number of novelties increase in the same scale, this is okay (for example, in Freeciv late game, techs come much faster). But this is rarely possible, and we can see many examples of games that have been ruined by not managing to deal with this increase in scale of chore tasks, or how otherwise good games have suffered from them.

In Civ2/Freeciv the best example of this is perhaps placing citizens. When you get a large number of cities, this chore becomes just impossible if you play with someone else.

Other chore tasks include managing many city production queues and moving large amounts of units around.

Micromanagement - the AI mistakeEdit

Some games 'solve' micromanagement problems by allowing the player to give more and more control over to an AI. This is a fundamentally wrong approach. The rules should work for the entire length of the game, and should not be solved by some 'deus ex machina' AI solution that allows you to play by the rules but not play with the rules. If the rules require such a cop out, they are not well designed. If in the first part of the game you play by one set of rules, one interface, and in the next stage of the game, due to the unwieldly number of game entities or production bases, you now must use a second set of rules and a second interface, then you have produced two games, not one game.

Once the game starts to be managed by a second-order AI aid, you get two key problems.

The first problem is that a human is still more likely to produce better results through continuing micromanagement than an AI is. This will lead some players to avoid the AI feature, but the resulting frustration with the overwhelming micromanagement will still be felt and produce negative attitudes to the game. Also in turn-based games, those who insist on micromanagement when the game designer thought players would use AI features will slow down the game for everyone else. Freeciv here is a case in point: turns proceed at the speed of the slowest player, and people who micromanage their cities are slow indeed.

The second problem is that, provided the AI feature is client-side in a client-server game, those who have the better AI scripts or AI code will gain a substantial advantage. This is particularly the case in multiplayer games that use a timeout timer to end turns. The unofficial Freeciv 'warclient' gives players mass control over units and is a substantial aid in timeout games. While some may find this (writing their own AI-aid code) a challenge on its own, it is inherently unfair and detracts focus from the core game concepts.

Micromanagement - the solutionEdit

It would be nice if one could reduce the number of production queues or abstract them away somehow. The current city report and worklists help a lot, but it is still a hassle to manage. One idea would be to pool all shield production globally, and the production queue would consist of item to produce, target city location pairs. In order to not make this too abusive, the flow of resources far away to a remote given city location should take several turns to achieve. The further away, the more turns. The better the transport tech, the less turns.

Another idea would be to separate how units and buildings are produced. One could use a global queue or a small number of global queues, the other the per city queues. Or just separate for some units. For example, in Master of Magic you could enact change in several ways. Some spells could be cast overland, to any visible map square, causing destruction at a distance or granting a positive effect. You also had a magic circle, which you could move around and from where special magical creatures could be spawned. These creatures often provided you with an extra edge in offensive combat. Our magic circle could be, for example legion barracks and the special units foreign legion. Legionnaires could be purchased with gold and take longer to recruit the less Fame you have (Fame would be another player attribute, victories give fame, losses remove fame). Improved technology gives you more units: legion phalanx, legion cavalry, legion tank, etc.

As for reducing unit micromanagement, there are several options. Movement is the major problem. In Master of Magic you could move an entire stack with one command, but this was possible because it did not have the lose all units in a stack scenario we have. If you can lose all units in a stack easily just because one lost combat, experienced players will just avoid stacks, plain and simple, making management of units even worse. IMO it would be nice if we had automatic combat between different stacks or armies, sort of like Civilization Call to Power or the Master of X games. The way Civilization III does it is is quite poor, but better than nothing. We could try doing that model as a first approach, since it is probably simpler to implement.

  • It's what Caravan/Freight units and railroads were originally designed for. They don't cost any production point to maintain and they allow developed cities to produce generic units (without any management) to be transported to developing cities to boost production. Although, Caravan/Freight should be recoded so that when they disband they give back 100% of their production costs to rebalance players favoring distributive development and players favoring centralized development. A fully developed city can easily produce north of 50 productions points each turn, so each turn can give the player 1 Freight unit per developed city. 8 such cities connected by a railroad on the home continent can gather them onto a Transport unit and ship them to the new colonies to dramatically speed up colony development.

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