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.
Contents
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]. That the fighting theme is not an essential aspect of Combos can easily be seen through the very similar actions needed to be taken in Dance Dance Revolution series and the Rock Band series).
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. Many of the powers in the fourth version of the role-playing game Dungeons & Dragons allow players to build strategy on possible Combos, e.g. making use of giving enemies vulnerabilities or setting up for attacks of opportunity.
Using the pattern
The original use of Combos in Real-Time Games required Timing and this has continued to be used heavily in for example games using Rhythm-Based Actions (Dance Dance Revolution series and the Rock Band series), but the pattern can be used more generalized in Turn-Based Games or simply any game where players need to create specific contexts, e.g. positioning Units in certain spatial configurations or simply which to bring them to game instances using Heterogeneous Game Element Ownership). The collection of Sets can be seen as Combos of actions that each fulfill a Gain Ownership goal, while allowing multiple Tools to be used together can also provide Combos. Repeat Combos show that Combos can be created from simply requiring players to repeat the same action several times within a given Time Limit.
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 growing 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. While Combat Combos often affect how Damage is dealt, it can have other effects such as introducing Movement Limitations (being 'slowed') or Downtime (being 'stunned'). Other type of actions commonly associated with Combos are Capture (e.g. Bejeweled and Hnefatafl), Movement usually not possible (e.g. Super Mario 64 or Quake), and Construction. Combos can also be created by letting players set up the effects of actions or events so that the coincide; adding Development Time or other Delayed Effects which players know when they occur makes this possible if they can try Timing their actions so they support each other.
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.
While the number of possible Combos can create Complex Gameplay, the complexity of performing the Combos that exist can be used to create both Complex Gameplay and Challenging Gameplay. While all Combos can be as complex as game designers wish them to be, those based upon growing Geometric Progression can allow players to succeed with variously long Combos and thereby provide Smooth Learning Curves.
The simplest form of making Combos possible to affect by others is through Interruptible Actions. For Multiplayer Games, the additional possibility of Collaborative Actions become possible since all these are forms of Combos, and Team Combos can be used to require participation by several players.
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. Given that Construction easily can provide many possible permutations, this pattern is especially likely to generate Combos. Although possible to counter by Evolving Rule Sets, Combos can easily occur from these as well due to the cumulative risk of unexpected effects in the design.
Interface Aspects
Games can make use of Progress Indicators to support players in learning Combos or to support Hovering Closures.
Consequences
Finding the time and context to perform Combos may require Tactical Planning, and Combos are often examples of Extended Actions that require Timing to be successfully executed. Combos based on Timing in Real-Time Games typically create Clickability as long as feedback is given on the progress of succeeding with the Combos.
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.
As mentioned above, Combos can give rise to Complex Gameplay and Challenging Gameplay and due to this the ability to execute Combos is a typically display of Game Mastery. A flip side of this is that Combos can cause issues regarding Player Balance due to them often having growing Geometric or Discontinuous Progression. For Turn-Based Multiplayer Games, the possibility to be able to plan for Combos can also cause Analysis Paralysis.
For games with Heterogeneous Game Element Ownership, Combos are likely to occur if not all game elements have the same gameplay functionality and these Combos give rise to Strategic Planning on identifying which exist and how to make use of them. The Strategic Knowledge developed in this manner is a likely source for Trans-Game Information exchange between players.
Combos can create Player/Character Skill Composites since the performance of actions may be influenced by Characters but performing them so that Combos occur may be a player skill.
Relations
Can Instantiate
Challenging Gameplay, Complex Gameplay, Configuration, Extended Actions, Orthogonal Unit Differentiation, Player/Character Skill Composites, Privileged Abilities, Tactical Planning
with Challenging Gameplay or Complex Gameplay
with Construction
with Geometric Progression
with Hidden Rules
Extra-Game Actions, Experimenting, Strategic Knowledge
with Heterogeneous Game Element Ownership
Strategic Knowledge, Strategic Planning, Trans-Game Information
with Real-Time Games and Timing
with Multiplayer Games and Turn-Based Games
Can Modulate
Combat, Construction, Damage, Movement, Score
Can Be Instantiated By
Collaborative Actions, Construction, Discontinuous Progression, Emergent Gameplay, Evolving Rule Sets, Geometric Progression, Heterogeneous Game Element Ownership, Repeat Combos, Rhythm-Based Actions, Sets, Team Combos, Timing, Tools, Units
Delayed Effects or Development Time if used together with Timing
with Progress Indicators
Can Be Modulated By
Hidden Rules, Interruptible Actions, Progress Indicators, Timing
Possible Closure Effects
Capture, Downtime, Goal Achievements, Movement Limitations, Penalties, Rewards
Potentially Conflicting With
History
A revised version of the pattern in the original collection in the book Patterns in Game Design[3].
