Language is kind of a funny thing. If you stop and think about it for a moment, you start to see that language is entirely made up. Letters and words are really just symbols with agreed upon meanings that we humans have devised to make communication easier. It is an excellent system in many ways, but it is nowhere near perfect. Language can be just as confusing as it is elegant, and it can be both at the same time. For one thing, most languages are in a constant state of change; new words are added, old words are forgotten, and what used to be considered vulgar slang gradually turns into polite terminology.

Another potential linguistic pitfall has to do with definitions. A basic assumption of language is that we all pretty much agree on the definitions of all of the words that we have made up to help us make sense of the world. Where there is disagreement about the definition of terms, communication starts to break down. And while we have dictionaries for a reference as to the “official” meanings of words, we all know that conversational language often does not conform to dictionary-based rules. Context matters and we often find ourselves involved in professions or hobbies that use language differently than any dictionary would lead one to believe.
When it comes to my favorite hobby, video games, I often wonder what people mean when they use the term “depth.”
Browse the forums of any strategy game community and the term “depth” will appear over and over. Depth is almost always considered a good quality in a strategy game. We want games that have it. Lists of superlatives applied to our favorite 4X games almost always include it. We read reviews to see if the latest game has it. We sharply criticize games that we believe are lacking in it. But no one ever seems to bother to define just what “depth” means.
If there is any agreement at all about the meaning of the term, it is a tacit agreement at best. Meanwhile, no one seems to ask what depth means either. Why does this happen when it comes to this particular term? Maybe it is because no one wants to admit that they don’t really know what it means. Using the term in the context of game criticism makes that person seem knowledgeable about game design, a savvy consumer and player. But to ask for a definition is to admit that one does not know – and who wants to admit ignorance on the internet? Whatever the reason, depth has become one of those odd terms that everyone uses but no one actually defines.
Naturally, all of this begs the question – when it comes to strategy games, particularly 4X games, is it possible depth? Or at least, can we come up with a definition that is workable enough for a particular community?

Of course, there is more than one valid answer to these questions and, as always, opinions will vary. But to me, ultimately, depth comes down to choice.
We cannot, however, just leave it at that. To say that depth is choice is well and good, but what exactly does that mean? Isn’t a strategy game essentially about making choices to begin with?
For choice in a strategy game to count as depth, those choices must be meaningful ones. Choices have to matter in order to be satisfying. Too often gamers have been presented with 4X titles that offer merely the illusion of real choice. Games with one or two optimal paths through the available options do not offer true depth. After all, why would anyone choose a path other than the optimal path once it has been identified? When this happens games quickly become boring, especially for astute gamers like 4X fans. Clearly inferior choices are quite simply false choices and do nothing but breed resentment in the minds of players.
But real, meaningful choices can truly change the way a games is played. Tall vs. Wide in the better Civilization titles is a decision that can quite literally affect every subsequent choice in the game. Meaningful choices show up in the game set up phase as well. Choosing a custom race in Master of Orion 2 with a trait like “aquatic,” “subterranean,” or “lithovore” each require different strategies for victory and can mean very different gameplay experiences.
But depth is an elusive beast. For one thing, depth in the context of 4X games is certainly not an all or nothing proposition. It is often the case that certain aspects of a particular game will be deep, while others will be comparatively shallow. To stay with the classic Master of Orion 2 for the moment, consider ship design. While there are many different systems and devices for the player to choose between, some weapons are just flat out better than others. There is some depth in some of the non-weapon ship systems but when it comes to firepower, there are certain choices that are demonstrably better options. Two people could reasonably disagree about whether or not Master of Orion 2 has real depth – it may very well depend on each person’s particular area of focus.

Then, of course, there is the question of complexity. Strategy gamers love complexity, it is a large part of what attracts us to the genre in the first place. But complexity does not always necessarily lead to depth. In fact, there are times when complexity actually creates the illusion of depth where there is, in truth, very little to be found. The research web in Endless Space is a particularly salient example. The research web certainly appears to be both complex and deep at first glance. It branches off in four different directions from the center of the screen and there are usually multiple ways to get to any particular technology. But the reality is that the research in Endless Space has no more depth than the very traditional looking horizontal research tree in Civilization V. As this becomes more apparent, successive games will find the player making many of the same research decisions over and over again, regardless of race choice and other, game-specific factors.
In the end, 4X gamers crave depth in our favorite genre. Choices are paramount because when you get past the fancy graphics and sparkly animations, 4X games are essentially about making choices. That is just what strategy is: making decisions based on a combination of long-term goals, known obstacles, and the situation at hand in the present moment. When a player realizes that his/her choices do not really matter, disappointment and frustration set in and the game in question quickly becomes boring. Real depth keeps a game fresh and interesting. It requires unique strategies from the player and provides multiple paths to victory. Real depth makes a game great in every sense of the word.
What do you mean when you use the word depth? Do you think depth equals meaningful choice or something totally different? Does every aspect of a 4X game need to be deep or is it more important in some areas than others? These are questions I want to explore for our community going forward. I hope this article serves as a kickoff in our quest to better study, analyze, and ultimately improve games in our beloved genre.
Nice article Troy, well articulated and brings up a critical discussion topic. Here are some scattered thoughts:
For a game to be deep strategically, I think it needs to regularly pose the player with meaningful (e.g. consequential) mid to long-term decisions. The decision horizon is really critical for depth – if your decisions only really matter for the next few turns and the game is mostly about adjusting the sequence of an optimal path through research and development, it’s more of a tactical game in my mind. It can still be a deep tactical game, but it may not be a deep strategy game.
You reference upfront choices, like deciding to go tall vs wide or custom designing a race. To me, that isn’t a direct manifestation of depth. These upfront decisions are more about providing variety in the starting condition that sets you up to head down different directions. The depth still needs to surface as you go down these divergent paths.
So depth needs to come out of the game state as it evolves during play. It’s not about the complexity of the systems and mechanics; it’s about the complexity of “the situation” – e.g. when you have to make a choice about who to go to war with (and more broadly how), or who to pursue peace with, or which region you target for colonization, or re-evaluating your mid-term technology plan based on the current game state, or how you want to deal with unrest or unexpected events, allocation of limited strategic resources, etc.
What makes the decisions above interesting, and hence supportive of depth, is when they are both ambiguous and consequential. For the latter, your decisions have to have a real bearing on your performance, otherwise they are just trivial decisions posing as something that matters. “Ambiguous” is tricky but important. Ambiguous means that you can’t be certain what the outcome will be exactly, which is to say the decision plays into a larger dynamic game state that is a challenge to ascertain and predict. Sure researching lasers gives me lasers 2 – but what is the opportunity costs and benefits long-term for having lasers 2 over something else? Hard to say!
Ambiguity is what opens up the door for player skill, the kind of player skill that you get from experience, not the skill that comes from looking up knowledge on a wiki or whatever. Developing skill and experience with a game is about building up heuristics, rules of thumb in a way, for good play based on navigating this ambiguity. Games with more depth have more levels of player skill that are obtainable, like how chess players have a skill rank.
And above all, I’ll repeat my mantra: complexity does not equal depth!