[In Ernest Adams' latest Gamasutra column, he digs into difficulty levels in games, interestingly suggesting that player-set difficulty can, in many cases, be preferable to dynamic difficulty settings.]
I just finished reading a book called Interactive Storytelling, by Andrew Glassner. While the first couple of hundred pages contain useful introductions to both storytelling and game design (for the novice, anyway), the book has some serious flaws and I can't really recommend it. But along the way, Glassner digresses into a variety of other subjects, and one of them is settable difficulty levels. He's against them. He thinks they ought to be banned.
This really pulled me up short when I read it. My opinion is exactly the opposite: settable difficulty levels should be mandatory in most game genres. In fact, I regard the lack of a difficulty setting as a Twinkie Denial Condition, except for a few kinds of games where they aren't suitable. Since I feel so strongly about this, I was especially interested in Glassner's objections to them. I'll take a look at, and respond to, his points before I go on to talk about his preferred alternative, dynamic difficulty adjustment (also known as adaptive difficulty).
These are Glassner's complaints about settable difficulty levels.
The player has to decide too early. Games usually ask the player to choose a difficulty level right at the beginning, and at that point the player doesn't actually know how hard the game is going to be because he hasn't played it yet.
My response: This isn't really an argument against difficulty settings. A game could easily give the player an optional training level at medium difficulty, and then allow the player to decide if he wants the rest of the game to be easier, harder, or about the same. But even without that, many players can make an educated guess about how well they'll play based on their experience playing similar games (I know I'm lousy at platformers), or they may choose a difficulty setting for other reasons.
I always start every game on easy mode, because I'm very busy and I want to see as much of the game as I can in as little time as possible. On the other hand, hardcore players carrying a heavy testosterone load routinely put every game on its hardest setting; that's how you get bragging rights.
The options are too coarse. What if medium mode is too easy, but hard mode is too hard? The categories are too widely spaced.
My response: There's no reason that player-settable difficulty has to be limited to three or four options; it can be a slider. Actually, any well-designed game varies its pacing so that regardless of its difficulty setting, it has easy periods and hard periods. Even arcade games give the player a breather now and then.
The difficulty setting isn't intended to determine the difficulty of every single challenge, only the maxima and minima at any given point in the game. I don't feel this is sufficient reason for banning them. I do have one requirement, though: easy mode is supposed to be easy. So easy you can win the game by pounding the keyboard with your forehead while rolling the mouse with your elbow. If it's not, the designer has somehow failed to understand the meaning of "easy."