Gamasutra - Difficulty Modes & Dynamic Difficulty Adjustment
Freelance writer and former game developer Ernest Adams examines the concept of player-determined difficulty levels in games in this Designer's Notebook article at Gamasutra. He begins by citing some objections to player-settable difficulty, and gives his responses:
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)...
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...
They're too persistent, i.e. a difficulty setting doesn't adjust to the player's rate of improving skill, especially if he's not allowed to change the setting later. The difficulty growth curve, at whatever setting, may prove to be too steep or too shallow for the player.
My response: This is undoubtedly a weakness of all games that don't do dynamic difficulty adjustment, but it's not actually an argument against settable difficulty levels. Settable levels don't create this problem; they help ease it little. Easy mode typically provides a very slow rate of growth in perceived difficulty, while hard mode provides a rapid one (sometimes described as a "steep learning curve"). Players know this and choose accordingly...
The rest of the article deals with dynamic difficulty adjustment, or an automatic level of difficulty in-game that's implemented by the game's responsiveness to the player's situation during play. Adams says players hate it, gives a variety of reasons and concludes:
I like the idea of dynamic difficulty adjustment in principle, because it appeals to me as a programmer. It would be very cool to code a game that was smart enough to adjust its challenges to the player's abilities, so as to guarantee him a good time. But...I also recognize that it's not necessarily easy to do.