Difficulty is a difficult subject. What makes a game harder or easier is intricately tangled in what makes it work as an experience: Just as you can’t take a difficult game and make it easy without losing something, you can’t take an easy game and make it hard without warping the experience and, often, making it unpalatable.
Some people like difficult games, some people like easy games. Some people like both. What is it that we enjoy about each, though? Difficulty is appealing because it conveys a sense of weight to our accomplishments in the game: When we succeed at a difficult challenge there’s a sense of elation, and it’s not really possible to fake that experience through other means (though many have tried). A difficult game can also force us to examine the game’s design more closely, study it deeply for opportunities to gain the advantages we need to succeed. However, it also means we’re probably going to spend a lot of our time with the game doing the same things over and over trying to get them right, feeling inadequate because of our inability to conquer an obstacle: Difficult games force you to learn them the way you’d learn any other skill, and to be comfortable with that you need to be able to face the possibility of being bad at that skill and spending repetitious time practicing to get better.
What the design of a difficult game requires, then, is for the game to be learnable. That is not necessarily to say easy to learn: The solution to a frustrated player is not necessarily a thorough tutorial. However, within the game causes should be closely tied to effects in a way that can be observed by the player. If this isn’t the case, the game will probably feel frustrating and arbitrary, with the player confused as to why they aren’t succeeding when it feels like the things they’re doing should be working. Though the Dark Souls games succeed well on this in terms of the moment-to-moment action, their stat systems are less successful in this regard, with many hidden effects and thresholds to trip up the inexperienced player.
Easy games are easy to like. Flowing through the game’s content effortlessly, the player is invited to feel powerful, to smoothly engage with the constructed content of the game at a planned pace, to experience things more or less directly as the designer intended. Not everyone enjoys that, though: some players might get bored, might feel the game is flattering them or pandering to them for accomplishments they had no hand in, may even feel like the game is lying to them for pretending that what they’re doing is impressive. In the worst case scenario, the player mentally checks out of engaging with the game’s systems at all, solving each problem by rote repetition of suboptimal solutions.
If we regard the difficulty of the game as being intrinsic to its design, then that means that changing the difficulty means changing that design. In that regard, having multiple difficulty modes is like having a set of similar but distinct games, kind of like alternate realities. Some of these games will work better than others: Players will get stuck more on the harder settings and not explore everything the game has to offer on the easier settings, but with any luck one setting will hit the sweet spot – but not necessarily the same one for every player. Some players will never end up playing the difficulty that provides the optimum experience because they believe, for one reason or another, that that difficulty doesn’t suit them.
Even though this optimum may shift from player to player, there tends to be a point where the challenge of the game is well tuned: Where the attentive and engaged player can succeed, where the structure of the designer can maintain, where actions feel consequential and consequences feel earned. This is the point of optimum difficulty. There’s another point of interest on the difficulty curve, and that’s the point of maximum difficulty. After a certain point, tuning a system to be harder will result in the breakdown of that system. Actually, it doesn’t break down all at once, but in pieces. For instance, say you took a normal FPS and made every enemy attack a one-hit kill: Much of the game would still function as intended, but the entire health kit and armor dynamic would be completely broken. If you also doubled the number of enemies, certain weapons that weren’t capable of the kind of crowd control that was now necessary would start dropping out. As you dial up the systems of the game to place a greater demand on the player, tools that the player used to cope with lesser versions of those threats start to lose viability. Eventually, all these tools fall away, and that’s the point where the game breaks. It isn’t necessarily literally impossible, but victory becomes a matter of luck or tedious grinding rather than the player’s clever usage of their resources.
One might ask: Why no point of minimum difficulty? To which I would say that reduction of difficulty is the act of disengaging the player from game systems. The point of minimum difficulty is therefore always the point at which you require no input from the player at all, which is the point where it stops being a game. I’m not calling games that don’t set out to challenge the player non-games, but I am saying that if you continue down that road to its logical conclusion you eventually end up at a place that’s not a game. Even the minimal asks of a game like Dear Esther, find out which way you’re going and walk there, is a challenge (of sorts) which requires the player to engage directly with the world.
Of course, difficulty isn’t everything. It isn’t even most of anything. But it’s worth keeping in mind that you can’t change how difficult your game is without touching the fundamental core of the experience, and that’s a step that you have to take mindfully. You can’t regard difficulty as merely a set of multipliers: At each level of the game, the difficulty is the design.