Gamasutra - Difficulty Modes & Dynamic Difficulty Adjustment

magerette

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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.
More information.
 
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What I actually never understood about sliders defining a game's difficulty,
is what they actually influence.

Or in other words: Which game elements become more or less difficult or easier within the game,
depending on how far I draw the slider to the left or the right.

I believe it would be good for the player to communicate that. At least, as long as it won't become a spoiler of some sorts.
 
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Some games do--I think NWN for instance, gives a little explanation along the lines of how spells work, how the AI responds, and stuff.

I'm playing HoMM3 today and it definitely explains the usual take for strat games: Easy=more player resources, fewer AI and the AI is handicapped, while Expert = player starts with almost nothing and the AI plays to the best of it's ability--(which is good enough to hand me my rear on a plate most times, btw. :) )

Technically, i guess, these games don't really apply because I don't think either has an actual slider, but that's the general idea.
 
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BG also tells you what effect you get from changing the difficulty level.

This seems like a non-issue to me. There's no compelling technical reason to NOT let the player change difficulty level mid game as long as it doesnt alter the availability of items and resources in the game world (things like monster HP can be scaled on the fly). You can have combine a few broad difficulty setting (easy, medium, hard with explanations) with a "custom" setting for more detailed tweaking.

Dynamic difficutly adjustment is a huge AI challenge and not really realistic in complex games in the near future if you want to go beyond level scaling. Finding a good evaluation function for player performance and a good difficulty function for the monsters is pretty darn tricky.
 
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I wouldn't exactly scale monster HP, since chances are that you already have lots of them spawned in your game world and then you'd have to update all of them. Maybe it'd be better to adjust the amount of damage the player does. Better, there should be AI adjustments, too. I think a game's difficulty sliders are much more interesting if the harder settings are actually harder because of smarter enemies or maybe less forgiving terrain.
 
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I dislike have no more control over the difficulty than an abstract slider. Flight simulators get it right. You can tailor your playing experience exactly the way you like. Yes they have pages and pages of options, but there's still an abstract slider for the masses who are scared by lots of options.

System Shock (1) got it right, at least for a non-sim. They had, IIRC, 4 different sliders controlling different aspects of the experience. I recall I always liked to play it (and on my many replays of that game) with everything maxed except the one which I set one less than max, because that final bit added a time limit. I liked playing it like a sneaker (stealth wasn't in the code, but it was still a reasonable option, and great for immersion), really slow and cautiously, so time limit was not an option.

I still cannot understand why that is not the norm. You can keep a single "master" slider for the masses while allowing fine grain control of the experience for the long tail.
 
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I wouldn't exactly scale monster HP, since chances are that you already have lots of them spawned in your game world and then you'd have to update all of them. Maybe it'd be better to adjust the amount of damage the player does. Better, there should be AI adjustments, too. I think a game's difficulty sliders are much more interesting if the harder settings are actually harder because of smarter enemies or maybe less forgiving terrain.

The challenge is to figure out what it is that makes an enemy smarter. AI is among the hardest things to get right in a game. We can do it pretty well for games like chess (producing an AI that both pass the Turing test and beats the world champion) where you have a somewhat limited state space and a limited number of player options, but computer games tend to have more degrees of freedom than chess. The chess AI is also mainly a brute force search engine function.

Still we can easily adjust things like AI line of sight and such on the fly, which in some sense makes it smarter. We could also, in restricted settings, let the AI cheat or have predetermined (seemingly) intelligent goals to make it behave like a clever human, but that isnt true AI.

A setting such as terrain would have to be fixed at the game start though, and the article seems to be focused on changing difficulty in the middle of the game.

I still cannot understand why that is not the norm. You can keep a single "master" slider for the masses while allowing fine grain control of the experience for the long tail.

I definitely agree. Strategy games tend to do this right as well. Imperialism or Master of Orion II are favourites of mine with good flexible difficulty options.
 
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