Combos
Sets of actions that trigger additional effects than those that occur due to the individual actions.
Combos are a sequence of actions that due to the order or configuration they are performed in trigger additional effects. The sequence of actions performed to create the effect can be seen as an action in itself, although more complex than ordinary actions and possibly interruptible even when the actions it consists of are not.
Examples
Fighting games such those in the Tekken series and Street Fighter series have only a few basic actions but by heavy use of Combos each character in the game can have the number of possible actions increased by an order of magnitude. The first of these Combos (in Street Fighter II) was due to programming feature but left in as a hidden possibility[1].
The height of jumps many of the games in the Super Mario series since Super Mario 64 can be extended considerably by pressing the jump button twice, resulting in a double jump. This maneuver is founded in several other games, e.g. as a special ability for the Scout class in the second installment in the Team Fortress series. Rocket Jumping[2] is a similar technique based on jumping while shooting rockets at the floor below oneself, and was an emergent feature in the Quake game.
To receive the Doctor achievement in Assassin's Creed 2 players have to first poisoned a non-player character and then successfully performing an air assault on the same character.
Combos do not need to rely on timing moves in a game. The capturing method of Custodianship in Hnefatafl can be seen as a Combo since it require two different piece to flank an enemy piece. When making one line of gems disappear in Bejeweled causes another to disappear, this is also seen as a Combo - players can plan for these and are motivate by the game system providing additional rewards for them.
Using the pattern
The original use of Combos in Real-Time Games required Timing, but the pattern can be used more generalized in Turn-Based Games or simply any game where players need to create specific contexts.
The design of Combos includes deciding if they should provide additional effects or simply modify the already existing effects, how complex they should be to perform and if their execution can be affected by others. Combos can simply modify original Rewards and Penalties through Geometric Progression or introduce new Rewards and Penalties through Discontinuous Progression. Combos are often used to provide Privileged Abilities, either as an additional Reward or as a way to provide Orthogonal Unit Differentiation - the latter especially common in Combat activities in Real-Time Games such as the Tekken series. The complexity of performing Combos can be used to set the Right Level of Complexity, for example by requiring Rhythm-Based Actions, in the game and can provide a Smooth Learning Curves as players can have the possibility to choose between performing simple actions or more difficult Combos. As with any Extended Actions, Combos offer the possibility of being Interruptible Actions independently of whether the actions they consists of are interruptible. In the case of Combos that are complex or interruptible,
in addition to any Privileged Abilities.
Interruptible Actions Analysis Paralysis Units Team Combos Heterogeneous Game Element Ownership Multiplayer Games Evolving Rule Sets Capture Collaborative Actions
Movement double jumps
Combos do not need to provide Rewards that directly affect gameplay. The most obvious choice is to modify how to add to the Score players are receiving, but Goal Achievements is another option.
In games with complex Combos, or games where players are encouraged to find the Combos by Experimenting, it is common to indicate when a player has started to perform a combo and provide additional feedback for each of the individual actions that has been performed. This can be done by Illusionary Rewards within the game world or by Progress Indicators providing Extra-Game Information.
All forms of Collaborative Actions are forms of Combos.
As some of the examples mentioned show, Combos can happen accidentally from a design perspective, but from the players' perspective this is more likely to be perceive as Emergent Gameplay and as a consequence this can be introduced into games to make Combos more likely to appear.
Interface Aspects
Games can make use of Progress Indicators to support players in learning Combos or to support Hovering Closures.
Consequences
Combos are examples of Extended Actions that require Timing to be successfully executed. Being able to perform Combos can be a goal in itself as it is actually a Configuration of actions - and this becomes especially true when they provide Goal Achievements (as in the Doctor Achievement in Assassin's Creed 2). Games where players know that Combos exist but are not provided with instructions on how to perform them, i.e. those that have Hidden Rules, encourages them to do Experimenting. In these games, knowing how to perform the Combos is Strategic Knowledge and can be shared as Extra-Game Actions.
Being able to execute Combos is a typically display of Game Mastery, but can cause issues regarding Player Balance due to them often having Geometric or Discontinuous Progression.
Relations
Can Instantiate
Configuration, Extended Actions, Game Mastery,
with Hidden Rules
Extra-Game Actions, Experimenting, Strategic Knowledge
Can Modulate
Can Be Instantiated By
Discontinuous Progression, Emergent Gameplay, Geometric Progression, Team Combos
with Progress Indicators
Can Be Modulated By
Possible Closure Effects
Goal Achievements, Penalties, Rewards
Potentially Conflicting With
History
A revised version of the pattern in the original collection in the book Patterns in Game Design[3].