February 5, 2015

The Snowball and the Steamroller: Fundamental Challenges in 4X Game Design


4X games are predicated on exploring some unknown geography, expanding your control into newly discovered regions, exploiting resources from those regions, and using those resources to build up forces and exterminate your opponents (who are trying to do the same to you!). Typically, 4X games aim to convey the machinations of entire empires, and hence have a large geographic scale in mind.  

This basic premise of large-scale empires fighting for resource control to fuel a military domination struggle creates some fundamental challenges for 4X game design, which has been central to whole quest to make the net big 4X game to live up to Master of Orion 2’s legacy.  I covered some of the failings of 4X games in an earlier post, A Failure to End, but want to expand on some of those points in this post. As I see it, the challenges are inter-related, but stem from a set of relatively simple issues:

- Issue #1 - City Spam & Snowballing
- Issue #2 - “One Big Battle” and the Steamroller
- Issue #3 - Micromanagement, Tedium, and Drag-out


These three issues are, I feel, the central challenge of 4X game design. And how the design of different games in the genre handles (or fails to handle) this interlinked challenge does as much to differentiate titles as to account for a game’s overall success, failure, or lasting legacy.

Edit: The awesome crew over at eXplorminate covered this topic from the perspective of the "endgame" experience: The 4X Endgame and its Follies and their article is also worth looking at in light of this fundamental challenge perspective.



Issue #1 - City Spam & Combating the Snowball

Typically in 4X games, controlling more territory gives you access to more resources, which can transpire into a force advantage to enable you to win the game. “City Spam” is the notion that good gameplay heavily incentivizes placing as many cities as you can, or taking over as many colonies/planets as you can, in order to control the most territory. And then there is “Snowballing” (think of the snowball rolling down the hill getting bigger and bigger). Snowballing is the notion that as a player gets a resource advantage over another player, they can apply that advantage towards growing their resource base at a faster and faster rate, and quickly surpass their opponents’ capacity. Thus city spam typically leads to snowballing, although snowballing can also be driven by other factors.



Limiting Management Units
4X games have tried to combat city spam in a number of different ways, one of these is limiting the number of management units directly. By “management unit” I’m referring to cities, colonies, planets, star systems, or whatever the “thing” is that houses your empire’s population, conducts production, etc. Basically, where a production queue is housed is probably what the management unit is.

Warlock 2 (for example) uses a system where only a few of your cities are fully under your control, and other cities get related to secondary support cities that help your empire but in a less direct and less powerful way. Endless Legends uses a region system where each large region can only have one city – hence hard capping the number of possible cities in the game.

These approaches aren’t particularly ideal solutions in my mind. One of the challenges is in rectifying such ideas as a compelling design mechanic in relation to their logical thematic implications. Endless Legend’s region system can be painfully arbitrary seeming at times, and doesn’t make much sense thematically. If no one is occupying these pre-defined regions, how did they even become named regions? What is responsible for determining their borders? From a gameplay point of view they do reduce city spam and they do force a careful consideration of where to place a city within each region as you expand. But it feels forced, a mechanic made to solve a mechanical problem and not one flowing nicely out of the theme.

Alternative Forms of Counter-Pressure
Another approach for dealing with snowballing is to keep the game highly interactive and give tools to the players (and the AIs!) to exert a counter-pressure on snowballing empires. This counter-pressure should come in ways that don’t fundamentally rely on the economic disparity that caused the snowballing to begin with. For example, this counter-pressure could come about through trade, diplomacy, or espionage systems. If for example, lagging empires could exert large trade sanctions or easily form temporary alliances to coordinate attacks (e.g. “Bash the Leader”) there’s a good chance of fighting against the snowball.

Unfortunately for single player games, getting an AI to behave in a coordinated manner is difficult, and likely explains why we don’t see more of this in 4X games. But in games with multiplayer support, this can be a critical aspect of the gameplay. Neptune’s Pride (and Diplomacy for that matter) are entire games designed around these diplomatic negations and pressures. There is the sense that if you get too big you paint a big target on yourself and get attacked on multiple fronts – hence you need to tread lightly and expand judiciously to not attract the ire of your opponents. This dynamic rarely exists in single player 4X games. Bigger is just better most of the time.



Diminishing Returns for Expansion
Last, snowballing can be countered through escalating marginal costs or diminishing returns. Basically, these are mechanisms employed to make continued growth more and more costly the more that you grow. Many 4X games introduce a bureaucracy type element or empire upkeep that consumes Gold or SpaceBucks as your empire gets bigger, making each new expansion hurt the overall efficiency of your empire. Other games use expansion disapproval type mechanics, where your citizens start getting upset and unsettled as your empire gets bigger.

The escalating cost system seems to be the better approach to solving city spam and snowballing in a more organic fashion. The game can be designed around a certain ideal empire size (number of management units) and players can chose to operate above or below that line if it makes sense strategically to do so. Unfortunately, this is also one of those situations where conveying the gameplay ramifications of such mechanics in a clear way is often hard to do. Many 4X games don’t provide a clear understanding of how these mechanics work and when they start to kick into effect, so learning the heuristics of good play is more frustrating than it ought to be. In addition, it often isn’t thematically logical that a big empire suddenly becomes less happy or less efficient due just to its size. In fact, bigger empires could be more diverse with people being happier as a result. Or economies of scale kick in and the empire could actually be more efficient! 


Issue #2 - “One Big Battle” and Stopping the Steamroller

The result of unchecked snowballing is that, for many in 4X games, matches are decided by “one big battle.” The player with the biggest production and military advantage presses the attack and corners a defender. If they are able to stack the odds in their favor in advance, winning a key fight is often a foregone conclusion. And once the bulk of the defenders army is destroyed the aggressor just “steamrolls” their way to an inevitable victory, with their forces uncontested as they take over the opposing empire.

Stopping the steamroller is wrapped up in the above issues related to snowballing. Minimizing snowballing can slow down the steamroller – but not entirely. Ultimately, the streamroller effect is tied to conflict mechanics. If two players enter a conflict with equal force strength (both are equally snowballing), but winner of the first fight only takes 25% or 50% loses, while the loser has been eliminated, the winner has a tremendous force advantage moving forward in the game.



Managing Force + Battle Size
One approach that many games employ to minimize conflict outcome disparity is having Force Size Limits. Endless Space and Endless Legends are two games that come to mind in this regard, where each fleet or army can only contain a certain number of units. This is another case where I think the mechanical solution can work but isn’t very logical or compelling from a thematic standpoint, and leads to other strange effects. In Endless Space, you can end up with dozens or more fleets all stacked in one location, which adds tremendous overhead to managing your forces and breaks what would be one awesome space battle into a series of smaller and less thrilling engagements.

Age of Wonders 3 has a fixed stack limit of 6 units per hex, and when battles happen the target/defender hex plus all seven hexes around them are drawn into the battle, allowing up to 42 units in a single fight (7 hexes * 6 units per hex). It’s similar to the army size limits that the Endless games employ, and it does dovetail nicely into how tactical fights play out. Yet the system does create its own idiosyncrasies with being able to the game system a little and stack the odds for a fight numerically in your favor. Having a mechanism for drawing in reinforcements of over the course of a protracted battle could be a cool expansion on the basic concept.

Civ 5’s “one unit per tile” (1UpT) system is also a move in this direction. In an effort to eliminate the “stacks of doom” we instead get a “carpet of doom” that makes even less sense thematically and in poses a more serious tactical-spatial challenge for the AI.

Starbase Orion (iOS 4x game) takes a more flexible and nuanced approach (like the flexible escalating marginal cost notion above). Ships require a certain amount of command points (think upkeep) across your entire empire. You can have more ships than command points, but it starts diverting credits away from the general coffers at a really high rate. Regardless, the command points system creates a soft cap on the maximum force size of any one player’s empire – which can keep players a little more even. Yet command points ramp up as your empire develops and grows, so a snowballing empire will just have more command points to support a bigger fleet. And with battles tending to be “all in” the outcomes of a single battle can still be decisive for the game as a whole.



Curious Conquest Mechanics
The conquest mechanics of many 4X games are, in my opinion, one of the more confused and underdeveloped aspects of 4X games. In so many games, eliminating a city’s or planet’s defending army lets you, relatively painlessly, take it over and claim it as your own. Rarely do games require a sustained occupation to convert population – an occupation which could dramatically slow down the steamroller effect and give time for the defender to regroup and launch a counter-attack.

Armada 2526 does a, conceptually, good job of tracking the population of different planets that you capture. When you capture a “alien race” star system, the system is still occupied by the civilians of the alien race – they are often not too keen on their new overlords and suffer major happiness woes as a result. These woes can cascade into revolts and rebellion unless you maintain a fleet presence to “keep the peace”, marines on the ground, or build security centers. An interesting detail is that you can’t actually build marines of an alien race as a way to keep the peace, so it can be quite hard to ‘tame’ a hostile alien population.

I’m still waiting for a 4X game that layers in some sort of cultural affinity system – where for example the population of empire A might really like the culture/people of empire B based on long-term cultural exchanges. This affinity would make fighting across these cultural line highly unpleasant for both sides, and put some counter-pressure on attacking and being overly aggressive.

Fighting on Multiple Fronts
Another, often untapped, opportunity is the extent to which 4X games encourage players to split up their force and be able to attack on multiple fronts. In so many games, the best strategy is to keep all your forces in one spot for maximum devastation when the battle comes. This can be a result of how combat is designed, but it also has a lot to do with strategic movement and intelligence gathering. If you don’t have a way of moving past or around a big fleet (either through speed or stealth or both!) to raid cities or planets behind the line then there is little incentive for players to keep their forces dispersed and defending (and attacking) in multiple different locations.

Age of Wonders 3 does a relatively good job of enabling this sort of play. Scouting and map awareness is critically important, but there are also an abundance of fast moving and stealthy units. It’s entirely possible for players to be in a cold-war state along the frontlines with smaller pockets of forces infiltrating behind enemy lines to try and steal weakly defended cities. Unfortunately, outside capturing cities there is little for a raiding part to do – you can’t destroy resource nodes or structures with your raiding party, and so are somewhat limited in your capacity do deal clandestine economic damage.

I’m not a fan of “star lanes” in space 4X games, but they do create a topography for space with choke points and the like that can make it possible for a compact defensive force to hold the line in some locations while you press the attack in other locations. So that’s another approach to encourage multiple fronts.

Uncertain and Unpredictable Outcomes
The more certain the outcome of a typical battle is, the more unfortunate the impact of the “one big battle can be.” Uncertainty can be a mechanism that keeps a stronger player from holding off on their attack, wondering whether or not they have the strength to win, or what the costs of victory will be. This pause in aggression may be enough to let a lagging player mount a stronger defense, which prompts the attacker to question their advantage again or enables the defender to attack on a different front.

One game that manages this notion well is UltraCorps. Fleets can contain 100’s or even 1000’s of units, the combined strength of which is all rolled up into a few firepower measurements. But the way the combat mechanic itself works is never a guarantee. Outside of doubling the firepower of your opponent, it’s often possible to sustain heavy losses or outright lose the fight even with a noticeable firepower advantage. A few lucky hits early on in a combat round that takes out a key capital ship, for example, can have a compounding effect on the course of the battle. The system keeps things tense and interesting and you are almost always going to sustain moderate loses in a fight.

Armads 2526 detection system also keeps players on their toes in a nice way and makes the gameplay more uncertain. Unless an enemy fleet is relatively close to a sensor array, you won’t know the exact composition of the fleet headed your way, you might only get an approximate number of ships in the fleet. If the fleet is even further way, it’s just a blip, and you have no idea of whether the fleet is a single scout or decoy, or a full on invasion force.

Persistent Damage of Units
This is a smaller concept, but one that that many games use to good effect. For example, in Starbase Orion, damaged ships remain damaged unless the fleet returns to a system with a Starbase and remains idle for a number of turns. This is a nice way of putting the brakes on an invading force, because even if you don’t win the big fight, you can still do a lot of damage and make the next fight easier (assuming of course you have more forced on hand). Unfortunately in Starbase Orion’s case, battles can often be quite decisive, and often a winning force will come out of the battle with minimal damage and loses, and if the defender went all in on the fight, it’s probably all over for them.


Issue #3 - Micromanagement, Tedium, and Drag-out

The above two issues, city spam fueling snowballing and the One Big Battle leading to the steamroller effect, combine with the desired scale of most 4X games to create very unsatisfying late game and end game experience for many. City Spam results in players having to micromanage a large number of cities or colonies – often more than players might want to manage to maintain their production advantage. Winning the One Big Battle then leaves the player in the position of having to “mop up” the waning empires in a tedious, drawn out affair devoid of tension or deep decision making. A lot players just quit the game at that point and call it a win.



Bring in the Micromanagers!
An often employed approach to minimize late game micromanagement is to rely on planet/system/city AI managers or governors. The theory is that as your empire grows and grows, you are less and less concerned with optimizing the output on each and every management unit, and hence are more willing (no delighted!) to relinquish control to an AI manager. Personally I find this a really unsatisfying approach – and especially when a game is close and the hour grows late. If I’m fighting for my life to keep a snowball/steamrolling opponent at bay, the last thing I want is an AI governor buying stuff I may not need and consuming resources and time in the process. Yet, if the game requires me to manage dozens and dozens cities/planets/systems as the only alternative, that isn’t a good prospect either!

Generally speaking, if a game as AI managers that operate in any sort of shadow, left to their own devices sort of way, red flags go up.

Better Living Through Technology!
A different tact is to give players tools that make management tasks easier even as the game scales up. One of the most brilliant systems I’ve seen in this regard is the “custom build focus” mechanic used in Starbase Orion. Briefly, you are able setup and SAVE a custom build queue depending on a particular goal you have in mind for the development of a given planet. This queue bulls from all of the possible planetary developments that can happen in the game. For example, you could create a custom “Research Planet” queue that includes all the +research buildings, but maybe also sprinkles in some +production buildings (to make research faster), and maybe at the end of the queue a Starbase or other special projects.

The game handles the queues perfectly and it dovetails with your technology progress – so if you haven’t unlocked “Research Labs III” the custom queue will move on to the next queue item that can be built. If there is nothing currently available to build, the queue can have its default behavior specified (e.g. generate more taxes, boost growth, stockpile production, etc.) so that you don’t need to bother switching the planet focus around manually. At any time, you can swoop in a manually override the queue with a new build order, and when that manual order is done the planet will revert back to its custom queue.

All in all, this system makes it possible to manage many planets and systems quite easily. It accomplishes the same goal as AI managers, but it puts the decision and tools in the players hand and keeps the process far more transparent.

Swift Closure and Alternative Goals
The tedium and drag-out of the late game is at its worst when players are required to effectively exterminate all of the opposing empires to win. If the only goal extermination, and you’ve already won all the possible one-big battles, and the steamroller is steamrolling and the snowball is snowballing, then what is there to look forward to? For all that I like about Starbase Orion, the end can be a slog when it’s clear you’ve already won. Providing alternative win triggers can be a good way to combat this issue.

Age of Wonders 3 has a pretty clever win trigger. Each player/empire has a single “leader” hero, and normally if they die your leader respawns at your throne city a few turns later. However, if you manage to kill someone’s empire and capture their throne city before they respawn, you immediately win! If course, this goal can happen at any time, and often you see players, especially in human vs human games, strategize around assassinating a leader and using concealed units to capture the throne behind enemy lines. This is great for keeping players on their toes throughout the game, but also works well to avoid the end-game slog. After the “one big battle” you can usually scout around and find the enemy leader and make a push right to their throne city for a win.

Age of Wonders 3 also introduced a clever “Seals” victory, which is a sort of multi-point king of the hill system. Maps will have a number of great seal locations (based on the number of players) and holding a seal earns you charges. A variable “charge limit” can be set for an automatic win. With the Seal victory condition enabled, players end up fighting a lot around the seals, pushing people off when they get close to winning in an attempt to secure a win for themselves. This system gives an alternative to cities for forces to target and fight over, and the charge limits functions a bit as an timer to prevent the game from heading into tedious endgame scenario.

Last, Age of Wonders 3 also has a nice “surrender” mechanic – where if you capture a bunch of an enemy empires cities in a short period of time, and you have a large force advantage, the AI will just surrender outright to you, with their leader and throne city coming under your control.

Of course, civ and 4X games have often had all sorts of alternative victory conditions (research, economic, cultural, diplomatic, etc.) – and these can be very compelling ways of minimizing the slog of end-game conquest. Of course, unless you are in a tight race with other empires, achieving these victories if often an underwhelming experience of hitting “next turn” for dozens and dozens of turns on end until you amass enough money, research, culture, population, or whatever to meet the win threshold. In other words, these can feel pretty anti-climactic.



Asymmetric and Unconventional Designs
A current trend in 4X game design, which I think is trying to solve all three of these issues at once, is to just radically rethink the entire formula for what it means to be a 4X game.

An asymmetrical design is one option, such as in AI War or The Last Federation where the “players” empire or domain of control is fundamentally different from the challenge they are up against. No longer is the human starting out in the same situation as the other AI empires. Instead, the human starts out operating in a completely different way from their opposition, and both have fundamentally different ways of winning or losing. In speculating, I think we’ll see a lot more advancement and experimentation with these ideas.

Other games have taken more of an unconventional approach to the empire builder. “At the Gates” and “Empire” (an iOS 4X game) have players managing a sort of roving/nomadic city-state-clan-thing that may settle down in an area for a period of time, but eventually be pushed to migrate and move to a new territory. These games are asymmetric as well, as there are no other roving/nomadic “players” that you are competing with. Nevertheless, they providing a compelling solution to the central issues. There is no snowballing per se because you are hard limited to just a few (or just one!) “management” unit. Likewise, the smaller scale and focus of the game relative to the asymmetric opposition you face makes steamrolling a non-issue. What are you steamrolling against in these contexts? It goes without saying that management tedium is largely a moot point as well.


Wrap-Up

The issues discussed above (snowballing, steamrolling, management tedium) and the various attempts at resolving them, has defined much of the 4X genre at a fundamental level. How different mechanisms are employed to combat these issues and how those mechanisms sit relative to the games theme does a lot to differentiate the core feeling and experience of different 4X games and speaks to multitudes of tastes and interests among 4X gamers.

Recent years seem to be a little golden age for 4X and civ-style games, and it will be fascinating to see how many of the innovative ideas and experiments will be received and which will stick on ceiling as a good idea for the future of the genre.

In the meantime, I’d love to hear your thoughts on these issues. Are there creative solutions to city-spam or steamrolling you’ve seen in games that I didn’t mention? Other creative ideas you’ve had to meet these challenges? The phones are open!


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