Skill–challenge relationship
A skill–challenge relationship describes the interplay between a game's challenge and a player's skill as they gradually improve while playing. The skill–challenge relationship is dependent on several factors of a game's design, particularly whether a game uses static difficulty or dynamic difficulty. This term does not refer to the increase in difficulty commonly seen as players progress in a game, only the relationship between a player's skill and a game's challenge.
Relationships
Four common skill–challenge relationships are described below.
Flat
In a flat relationship, the game uses static difficulty and the challenge is predetermined by the designer. Since it never deviates, the challenge remains flat over time. At the beginning of the game, the challenge is typically greater than the player's skill, but, as the player plays the game, their skill will improve, and, if they keep playing, they will eventually master the game, thus the steady rise in skill. Although the challenge doesn't change, the game feels easier to the seasoned player simply because they've gotten better. This relationship is seen in a lot of early video games like Donkey Kong and Pac-Man.
A downside of this relationship is its fixed learning curve. If the game is very challenging, there is nothing a player can do to to decrease the challenge, and countless game overs may discourage the player long before their skill increases to the level where they can master the game, if it ever does. On the flip-side, if the player finds the game too easy, there won't be a challenge, and the player becomes bored. A game can introduce multiple difficulty levels, but this just changes where the challenge line is drawn along the X axis, it still remains flat. Many gamers actually like this relationship seeing it as the true intent of the designer. After all, if the game has to make special concessions for you because you weren't skilled enough to win, did you really win?
Equal
This relationship uses dynamic difficulty where a game adjusts its challenge in an attempt to stay on pace with the player's skill. In reality, the skill–challenge relationship is never as linear as depicted in the illustration, but this is the ideal. This relationship can be seen in games which are strongly influenced by dynamic difficulty like Mario Kart 64 and Left 4 Dead.
This relationship is more modern and has proven very popular at attracting new players. The game starts fairly easy to appeals to amateurs, and, by keeping pace with the player's skill progression, the game is sure to provide a consistent challenge. And, if a very skilled player starts a new game, it will quickly adjust to meet their skill with a harder challenge. A difficulty with this relationship is maintaining the balance between skill and challenge. If the game doesn't become hard enough fast enough, or becomes too hard too fast, you get one of the curved relationships below. This relationship can also introduce a lack of a feeling of accomplishment. If the player knows, no matter how good they get, the game will just keep getting harder, there isn't an end goal in sight. Because of this, many games which use dynamic difficulty also have a difficulty cap so a skilled player will still eventually overcome the challenge. Knowing where to put this cap is another difficulty with this relationship.
Reducing
A reducing relationship describes a game where the challenge decreases as the player's skill increases. In this relationship, the game doesn't just feel easier because the player's skill increases, the game actually becomes objectively easier as the player gets better. This could be the result of poorly-calibrated dynamic difficulty, but it's also a side-effect of static difficulty paired with a power-up system which rewards skilled play.
Consider a scrolling shooter like Gradius or Life Force. These games feature power-ups which improve the player character's maneuverability, firepower, and defense. As more of these power-ups are acquired, the game's challenge actually decreases because the player can more quickly defeat enemies before they can retaliate. A skilled player is more likely to acquire and hold onto these power-ups, and, therefore, the game becomes much easier for them. This power-up system is very common, seen in shooters like Contra, platformers like Super Mario Bros., action adventures like The Legend of Zelda, and even in role-playing games like Final Fantasy, many of which have optional treasure chests containing beneficial items, which skilled players are more likely to get.
Because this relationship is so common, few players have a problem with it and just see it as standard game design. However, because the challenge decreases in proportion to the player's skill, it increases the likelihood of the player becoming bored as they become more skilled. Preventing this is no easy task considering it is directly caused by rewarding skilled behavior with power-ups. The game design would have to change drastically to alter this relationship. For example, a game might give the player power-ups at the onset, and then take them away as they do better, but having your power-ups taken away is a punishment for skilled play, not a reward.
In order to keep their interest, many players create self-imposed challenges for their favorite games, and many games today actually incorporate these directly into game play.
Growing
A growing relationship is pretty rare and it requires the game to not just become more challenging to match the player's skill, but create a growing increase in challenge as the player's skill increases. This is typically the result of poorly-calibrated dynamic difficulty. I don't know of many games that do this. The only example I can think of is Ultima: Exodus, an RPG where, as the player improves their ability and levels-up their characters, the game starts spawning increasingly difficult monsters which outpace the strength of your party.
The downside of this relationship is that players typically see it as bad game design. Meeting a player's new skill with an equal challenge is one thing, but few players want to be punished with increasingly difficult challenges the more they practice. How players get around this can be seen in a common strategy in Ultima: Exodus, players purposely keep their party low-level and play as though they're still a beginner in order to stave off the most powerful monsters for as long as possible.
Personal
I was watching a video about how Nintendo uses dynamic difficulty to assist unskilled players, and this got me thinking about how so many older games become easier as the player's skill improves, not just because the player is better, but the game itself becomes easier. This led me to thinking about the relationship between a player's skill and the game's challenge.
