How Interfaces of Competition Shape Games
Excluding single player and cooperative games, players compete against each other for victory. Game designers are tasked with making this competition interesting. In order to do this, they must think carefully about the level of interaction, and the interface by which the players in their game compete.
Player versus Player Interaction
When someone is playing a game they are interacting with various elements. This interaction may be with the game itself, or it may be with the other players in the game. When the interaction is between players, I will call this a Player versus Player (PvP) Interaction. This is somewhat of a spectrum but here are some examples:
In Starcraft 2, when they are building a worker such as an SCV, this is an interaction with the game. When they are using a unit to attack the enemy such as a marine, this is a PvP Interaction.
In Magic the Gathering, when they are drawing a card or tapping mana, this is an interaction with the game. When they are blocking an opposing player’s creature, this is a PvP Interaction.
Degree of PvP Interaction
Different games will have different levels of PvP Interaction throughout the game.
One major indicator on the degree of PvP interaction is how much attention players pay to the other player’s moves.
In a game like chess, you are likely paying attention to every single move your opponent makes. This is because every choice they make will likely have an influence on how you play. Chess is a game with an extremely high degree of PvP Interaction.
In other games, the only point you might interact with your opponent is to compare a score at the end of the game, with the higher score winning. This would be a game with a low degree of PvP Interaction.
One more thing to note. The degree of PvP Interaction should not be confused with the skill required to play a game. Some games can take a serious amount of strategic planning, without having to account for another player’s choices. The more skillful player will be sure to come out ahead, even if there was not a lot of PvP Interaction along the way.
Interface of Competition
When 2 players interact, a set of rules will create an interface by which they compete to get an advantage over each other. Typically these rules must be dynamic enough that they may allow for one player’s choices to outshine another’s in order to result in an interesting game.
Example Interface of Competition: Battle Phase in Magic the Gathering
In Magic the Gathering (MTG), both players have 20 life points to start. If a player is reduced to 0, they lose the game.
Note: There is also a lose condition where you draw with no cards in your deck, but it is not important to this example.
There are several card types, but one of the most important types is a “creature”. Creatures have a power value and toughness value.
Every turn a player takes has a combat phase. This is broken down into 3 main steps:
A player may choose to attack with one or more creatures.
The other player may then choose to block each attacker with one more creatures. Each blocking creature can only block one creature.
The creatures then deal damage simultaneously. Blocking creatures deal their power to the attacker they are blocking, and attackers distribute their power amongst defenders. Any creature that takes damage equal or greater than its power is killed in battle and removed.
Any attacker that was not blocked, will deal its power in damage to the opposing player, subtracting from their life points.
This battle system creates an “interface” by which both players use the rules to compete. Players will try to get an advantage over the others by individual choices and plays, which ultimately feed into combat. This system has become the “interface of competition”.
This set of rules is pretty basic by itself. In collectable card games (CCGs) like MTG most of the complexity will come from the variations in the card’s power and toughness values, and the rules text that is printed on individual cards. This makes them a great example for systems with simple interfaces, but a lot of depth and variation between players.
Asymmetric Design and the Dangers of Breaking the Interface
Asymmetric design can create an interesting battle of styles.
I am personally a huge fan of asymmetry, and it’s one of the main aspects of CCGs that draws me to them.
However, a game designer must be careful with asymmetry. Asymmetry can seem exciting, but can interfere with the interface of competition in a way that it can be completely broken and this may be frustrating to players.
This is not to say that mechanics like these should be completely avoided, but Game Designers need to be aware of the consequences and at least put them in their game with careful but clear intention.
Exodia in Yu-Gi-Oh
Yu-Gi-Oh! is a CCG with a similar win condition to MTG in that the goal is to reduce your opponent’s life points to 0 with attacks from your Monster cards (playing a similar role to Creature cards). The Monster cards may also protect you from your opponent’s attacks.
Exodia the Forbidden One is a card that reads:
If you have "Right Leg of the Forbidden One", "Left Leg of the Forbidden One", "Right Arm of the Forbidden One" and "Left Arm of the Forbidden One" in addition to this card in your hand, you win the Duel.
Alternative win conditions are awesome! Some players want nothing more than to say “screw what’s normal, I’m going to win with style!”
However it introduces a problem to the game. The interface of competition of Monster on Monster combat is completely irrelevant. This breaks the interface.
In decks in Yu-Gi-Oh! that actually try to assemble Exodia, this also becomes apparent. They typically take the style of trying to draw cards and stalling out the game by preventing your opponent from attacking. The question of who wins often comes down to whether they drew their cards in the right combination, or if you drew something that can disrupt their stall plan. It can feel like the Exodia player turned the game into a coin toss, rather than a dynamic one with back and forth combat.
Flying in Magic the Gathering
In the summary from above, we described how the blocking player can choose to block creatures with their own. There is a common ability on creatures called “Flying”. When a creature has Flying, it means that it can only be blocked by other creatures with Flying.
Flying creatures soaring above the rest is indeed intuitive and thematic, however it breaks the interface of competition. No longer can one side use their creatures to block the enemy Flyers, and this could mean that the game feels less interactive (in Flyings case, particularly on one side of the match up as the Flyers can block non-Flying creatures).
In MTG, mechanics like this are often described as “evasion” mechanics. In the past, evasion mechanics were often designed in a similar way to Flying, where the interface gets ignored. Nowadays, the designers are trying out new ways to create more interactive mechanics that still provide “evasion”. An example of a mechanic is “Menace”. A creature with Menace must be blocked by at least 2 creatures. This makes it more difficult to block, but any deck that gets at least 2 creatures will be able to interact with it still. This means the blocking player will often still face interesting decisions.
Designing with Intention
The Degree of PvP Interaction and the Interface of Competition are going to be two key drivers to the audience that is attracted to your game.
Increasing the PvP Interaction may result in pushing away more casual players. When the game has players of varying skill playing against each other it may also create a less than fun experience for the newer players if other players can interfere with them too much.
However, decrease the PvP interaction too much, and a different audience will complain that it is like playing solitaire in the same room.
The Interface of Competition on the other hand, should be carefully designed for depth and dynamicness. If you are breaking the interface, make sure to do it with a specific purpose in mind. The tradeoff between the interest of a new strategy and the frustration caused to “fair” players should be carefully tuned.
For example, when adding an Exodia-type strategy to your game, you may want to ensure it is less powerful than the majority of normal strategies in your game, and wins at a reduced rate. This allows players who seek out alternative win conditions to enjoy it, while preventing it from becoming a dominant strategy.
As you can see, any combination can result in a great game. But in order to be successful in delivering the type of game you want, you need to keep these axes in mind and make sure you are designing with a coherent path forward.