There are a number of ways of looking at difficulty in games. Here I'm going to discuss only one aspect, the distinction between obvious and obtuse difficulty. (Jesper Juul has conducted a lengthy analysis of the nature of game difficulty, if you're interested in a more extensive study).
When someone says a game is “fun,” there's a great deal of variance in what they are actually referring to. A game might be “fun” because it tells an engaging story, because it makes the player feel skillful or because it makes the player laugh. Similarly, a game being “difficult” is a vague quality. It could be difficult because the controls are bad. It could be difficult because it's punishing and bordering on unfair or because it hosts complicated and cryptic puzzles.
As designers, we cannot be content to think about our games as “easy” or “difficult.” Rather, we must think about the experience we want the player to have when engaging with our game's difficulty. Failing to be rigorous here and just making a game “hard” is likely to result in a game that's frustrating rather than enjoyably difficult.
And indeed, difficulty can be enjoyable. In fact, as evidenced in Jesper Juul's study linked above, players are more likely to be critical of a game that's too easy than too hard. This does make sense; if a game is too hard, practice might result in player skill improving to the point where they can succeed. But if a game is too easy, nothing short of self-imposed handicaps (taping your thumb to your palm?) can make it harder.
To be clear, this is not making a value judgment on difficulty. There are some players that long for the Ninja Gaidens and Devil May Crys. But difficulty is something that should be constructed with intent rather than by neglect. Neglectful difficulty often ends up as obtuse difficulty. By obtuse difficulty, I mean challenge that arises from the player not knowing what needs to be done in order to progress. The opposite being obvious difficulty, where the player knows what to do and just needs to improve upon some skill to achieve it.
Obtuse difficulty is problematic because it's often the case that there is no reliable way to move from this blocked state. Players can easily become frustrated with this kind of difficulty, and understandably so. Would soccer be as enjoyable if the rules changed every game and the players only discovered them when they received yellow and red cards for violations? Puzzles are especially susceptible to this, which I discussed here. Readability is a measure of how clear the relationships between actions in a game are and games that seem simple are often just readable. Simple is often used derisively to describe gameplay, but it's actually something more developers should strive for.
This doesn't mean that puzzles are inherently inappropriate for games. But it does mean that most players require meaningful feedback when attempt to solve puzzles, something that rarely occurs when difficulty of sort arises out of neglect rather than intent. Thus we ought to approach difficulty with a clear idea of what we want challenge in our games to emerge from. Envision how the difficulty will feel and then focus on creating that experience.
The recent trend toward simpler games is, I think, partially an attempt to avoid this kind of difficulty, and I think it's a laudable goal. Something like And Yet It Moves offers a single, simple core mechanic and the challenge arises from how to apply it. This is not the kind of challenge all games should offer, but it's very appropriate for the kind of experience And Yet It Moves was trying to create. The important thing to take from this is that difficulty is a broad category for many different kinds of dynamics. Understanding the nuances of different kinds of difficulty and intentionally create the one most appropriate for the desired experience may produce games that feel “simpler” but ultimately, as just more enjoyable to play.
Nels Anderson is a programmer at Hothead Games. He's probably the only game developer in Vancouver (and maybe all of