Examining Game Pace: How Single-Player Levels TickBy mark davies
[In this in-depth article, veteran designer Davies looks at games from Call Of Duty 4 through Dead Space to analyze the art of game level pacing.]
"Pacing" is a word bandied around a lot when talking about level design, but it is actually a very complex concept to pin down. Just how does the pace affect the player's perception of the level and what is it that sets a well paced level apart from a poorly paced one?
With these questions ringing in my ears I was determined to try and delve a little deeper into just what constitutes level pacing, but I found very little literature on the subject. Instead I decided to focus my efforts on breaking down the core elements of what determines pace itself.
In doing so I identified several key aspects of game pace:
- Movement Impetus -- the will of the player to move through the level.
- Threat -- the notion of danger.
- Tension -- the atmosphere and mood of the level or perceived danger which is reflected in the player.
- Tempo -- the level of actual action currently being experienced by the player.
Movement impetus is the will or desire of a player to move forwards through a level. There are several ways in which the player can be pushed into moving or stalled from pushing forwards in order to affect the movement impetus and thus the pace of the action.
There are many elements that increase impetus to move:
- Introduce a threat from behind -- as long as the threat is significant it will cause the player to want to move away from it.
- Present an objective ahead -- dangling the carrot is one of the most effective methods of encouraging movement. A clearly defined goal is vital in creating this urge to follow it.
- Impose a time limit -- quite obviously the restriction of a time limit will encourage the player to not hang around. Too many imposed time limits can be extremely frustrating however.
- Narrow physical options -- limiting the space in which to travel -- i.e. long corridors as opposed to open spaces, limits the amount of choice available to the player and in turn increases the speed at which they tend to move.
- Draw the eye -- items of interest will pull the player towards them. Judicious use of these will help to pull the player through parts of the level. Bear in mind that once they reach the item of interest they are likely to pause at that point.
- Architectural pressure -- specific forms of architecture promote movement. Walls that angle down, long corridors, junctions, etc all have psychological impact upon the player.
- Snatch desired object -- taking away a desired object will often trigger the player into chasing after it.
- NPC leads the way -- having a third party lead the player though the level will nearly always directly affect the movement impetus.
Continual movement keeps the tempo high, but it is undesirable in many ways. Often players want time to take stock, catch their breath, formulate a plan or even just soak up the atmosphere -- it provides a break from constant travel. Also in production terms continual travel often requires much more real estate in which to move -- this is both a production risk and possibly a technical issue.
Conversely there are also many elements that decrease impetus to move:
- Wow moments -- stunning scenery, dramatic actions, impressive vistas or other elements that halt the player for a while.
- Obstacle -- something blocking the progress ahead will decrease movement impetus and force the player to find a way around or a way to clear the blockage.
- Altered movement -- a different movement method may require more thought, such as scaling walls via handholds.
- Introducing a threat ahead -- a group of enemies ahead, a flaming pit or any other potential threat will slow the player whilst they plan to deal with it, then execute said plan.
- Increased tension -- when tension is particularly high (usually through a high perceived threat and good atmosphere) then the player will often be fearful of moving quickly. Dead Space is a classic example of this -- many players tend to move slowly to ready themselves for sudden attacks.
- Multiple Routes / Open World -- choice requires thought and thought slows movement impetus. Multiple routes and open world games offer a plethora of choice. Perhaps the ultimate example of slowed impetus is the moment when a player exits the sewer in Oblivion and sees the huge expanse of the world before them. It takes a moment or two just to take it all in.
- NPC halts player -- just as an NPC can lead the player, they can also halt the player or slow them down.
- Taking stock of inventory (collecting items) -- whenever a player encounters an item they are likely to slow down to investigate. Complex inventory systems will also require management that will slow movement impetus. Further still -- having collectible items in the first place will encourage exploration.
- Dialog / Roleplay -- moments of dialog with NPCs or getting into the character will generally require more involvement from the player, and will thus slow movement impetus.
- Story exposition -- generally the exposition of story will require the player's attention and will thus slow movement impetus.
Constantly slowing movement impetus can also be dangerous, as it can prevent the player having a feeling of progression. A balance needs to be struck in providing a sense of movement and accomplishment and allowing the player time to themselves to explore, soak in the atmosphere or to take stock of their situation.
Threat (Actual Danger)
The pace of the game can also be increased by the sense of peril that is experience by the player. The more threat the player believes they are under, the quicker their pulse, the more nervous and often more panicked them are.
Threat can come in many forms -- each form having a different feel of pacing. For example combat tends to be more frantic and higher paced than traversing an environment, even though the end result -- death -- could potentially occur in either situation.
Generally the level of threat felt by the player is determined by whether the threat is being caused by an external force -- an enemy, an encroaching hazard, etc, or whether is a danger that will result from the player's own mistake. Threats from external forces tend to have a much higher level of pace than those that will result from a player's mistake, as they have time to gather their thoughts and create a plan when they have control.
Proximity of a threat also has a huge influence on the feel of the threat. An enemy at a distance is not nearly as threatening as one very close by. This is something that stealth based games can really use to their advantage (and is something that can also build a great sense of tension).
Adding a time limit to a task automatically increases the level of actual danger, as the control the player has over the game world has been reduced -- there are now limits placed upon them which can induce a level of panic.
Tension (Perceived Danger)
Tension occurs from the belief in an unknown danger and can be difficult to achieve, but the result of achieving it can be incredibly immersive. Tension works particularly well in creating the right pace for a horror game.
In order to create tension the right atmosphere must be created. A world has to be crafted that the player can invest in, believe in and ultimately become immersed in. Audio can help a great deal in building tension. Music in particular can create tension by playing to well known triggers that people have learnt from years of films and TV shows.
In truth, whilst tension is created from fear of the unknown, the threat must be known in some way. Take the game Alien Vs Predator, which I feel has possibly the most tense introduction level of any game I have played.
Throughout the level your motion sensor blips and flashes as threats apparently come near you. However, this sequence heavily relies on the player's knowledge of the films to know that the flashing blips on the radar could potentially be the deadly aliens.
To achieve tension when you don't have the luxury of a well-known license to rely on, then you need to show the potential consequence of the threat, or the threat itself in some form. Dead Space does a very good job of building up tension without the player immediately knowing what the threat is. As soon as they board the Ishimura it is plainly obvious that something is seriously wrong.
Tension can also be achieved through a known threat in stealth games. Instead of a fear of the unknown, the tension comes from the fear of being discovered. Games such as Metal Gear Solid and Splinter Cell utilize this fear well by forcing the player to engage in tense scenarios with enemies in close proximity.
Tempo describes the level of intensity of action -- how much concentration is required by the player to achieve their goal. Low tempo gameplay tends to be that which requires serious thought and contemplation -- generally puzzles. High tempo gameplay is generally gameplay that requires fast reactions and split-second decisions. High tempo action often induces stress or panic and often at its highest level might be termed "frantic".
There is always a sure-fire method of creating high tempo no matter what the situation -- by imposing a time limit -- or what could be called "Forced Pacing".
Tempo in Movement
Tempo when moving around the environment is determined by the mechanics of the game and the environment itself.
Explorative movement tends to be low tempo, as the player has time to look around and determine their own route.
More acrobatic environment traversal can often be higher tempo. It really achieves high tempo when there is a great sense of flow in the design. A great example of such flow is the Prince of Persia: Sands of Time -- the mechanics and level design merged to create patterns of flow that had high tempo.
Tempo in Puzzles
Puzzles by their very nature tend to be low tempo -- the only real way to create a high tempo puzzle is to add a time pressure. This tends to make them the ideal method of reducing the pace of gameplay as a counterpoint to high paced action like combat.
Tempo in Combat
Combat is usually high tempo as it will require split-second decision making and requires high levels of reaction. The tempo itself may change dramatically over the course of a battle.
A general battle against a group of enemies in a game tends to follow a bell-curve pattern. The tempo of the battle builds to a certain tempo before it hits a turning point, where the more the player removes the incoming threat, the easier it becomes to take out the remaining threats.
For example, a Left 4 Dead horde encounter follows this pattern -- the initial build up of enemies increased fairly rapidly up to a maximum number and a frantic tempo, before the player manages to destroy enough to turn the tide of the battle. At this point the lesser numbers make it easier to kill the remaining zombies and the tempo drops off.
Boss fights tend to have much more of a crescendo feel -- they are generally eased into the first part of the fight, but as they start to chip away at its health it begins to attack with more and more ferocity, until the final phase where it is particularly dangerous. Of course once it is defeated the threat has been completely eliminated the tempo drops to pretty much nothing.
Structure of Pacing
Whilst knowing the fundamentals of pacing is important, it is the way these fundamentals interact with each other -- how they are structured -- that is truly important.
The key to creating a well paced level is to provide moments of action interjected with calm - peaks & troughs as they are often called. Keeping at a trough for too long can become tedious and lack excitement -- remaining at a peak for too long can desensitize a player to the action, to the point where it becomes repetitive and boring.
I heard a fantastic analogy from a designer recently -- that pacing a level is much like composing a piece of music -- he liked to structure it as verse followed by chorus, followed by verse, etc.
I thought this was a really good way of looking at it, as music has much the same job to accomplish -- create an emotional response in a manner that changes over the course of time - the only difference is the level of interaction.
In a way playing a level is more like being a musician interpreting a piece of music.
So are there elements of music theory that could be applied to level pacing?
The main elements of a piece of music are:
- Rhythm -- in music rhythm is the timing of particular notes. In gameplay this could translate as the timing of events that determines game pace.
- Melody -- describes notes in a successive series to create phrases of sound. This could be comparable to a sequence of events in a level to create phrases of gameplay -- something that might be termed Flow in game design.
- Harmony -- is the combination of notes of different pitches to create pleasing sounds, something that can easily be equated to combinations of game mechanics within a sequence to create a pleasing play experience. Some mechanics will gel well together and some will not -- much like musical notes.
- Form -- the structure of a piece of music. Potentially this could be applied to the organization of gameplay events to form particular patterns.
- Timbre -- the quality of the note. This is generally related to the type of instrument that creates it. This could be applied as the different types of mechanics used to produce the desired gameplay.
- Dynamics -- refers to the volume or sound of a note. This could translate to game design as the specifics of a particular piece of gameplay, such as the numbers of enemies used in a combat sequence or the height and length of jumps in a platforming sequence.
- Texture -- describes the amount that is going on in a piece of music at any one time. In gameplay this can simply translate as how many different things are happening at any one time.
The main element of rhythm that applies to level pacing has really already been covered -- tempo -- the feel of intensity that the player experiences from moment to moment, how fast they feel the pace of action to be.
Tempo can be altered during the course of a piece of music in a number of ways. There are specific terms used in music to address changes in tempo:
- Accelerando -- gradually increasing (accelerating) the tempo. This is very applicable to level pacing as it is often the case that the average tempo of the level increases towards the end.
- Calando - going slower than previously. This would decrease intensity of gameplay over the preceding section.
- Precipitando -- going faster than previously. This would increase intensity of gameplay over the preceding section.
- Ritardando -- gradually decreasing the tempo. This may not apply across a whole level, which generally will increase in tempo, but might occur after particularly fraught sections -- rather than simply drop the pace completely it may bring it down gradually.
- Ritenuto -- slightly slower than the previous tempo, holding back. This might be used in level pace to punctuate a battle with a smaller skirmish before returning to a larger battle thereafter.
- Stretto -- temporarily speeding up. This would be a change to bring up the intensity of the gameplay or raise the challenge for a short time.
These changes may be sudden or happen gradually. In level pace these tempo changes are likely to occur very frequently -- much more frequently than they would in a piece of music.
Melody in reference to music describes the pattern of notes. We can apply this to level pacing as the pattern of game mechanics that make up a sequence -- more suited to the term flow.
There are several terms used to describe aspects of melody in music that could be applied:
- Monotone -- the repeated use of a single element.
- Ostinato -- a repeated phrase or game mechanic (separate to monotone in that it is punctuated with others).
- Ornaments -- elements that are used to embellish the principle element -- i.e. smaller game mechanics in a sequence that focuses on one particular mechanic as its main theme.
- Tremolo -- rapid alternation between mechanics.
Harmony is the combination of notes to create a pleasing sound -- a chord for example. In terms of game pacing this might be interpreted as mechanics used in unison to create pleasing gameplay. Certain types of gameplay tend to fuse well, others are so different that they are discordant -- they don't work well together and feel wrong.
The form or structure of a piece of music describes the manner in which it is assembled -- breaking it down into constituent parts.
The most common musical structure is the Strophic form -- verse, chorus, verse. This could quite easily apply to pacing: choruses tend to be louder, more impactful sections between quieter and more relaxed verses. This is very similar to the peaks and troughs ethos of many games' level pacing.
There are however other structures used in music that might also be applicable. Rondo (to return) plays a different melody each verse, but returns to one main theme each time. Other structures are very much like mini narratives, such as Fugue or Invention, which tend to have exposition, then development and then finished with recapitulation. Variation has a main theme that is played slightly differently each time.
There are certainly some elements of musical structure that might well translate well to the feel of level pacing in a game.
Translating timbre to game pacing is really describing the quality of the gameplay as its constituent game mechanics -- it defines exactly what is required of the player.
An examination of timbre is to break down the individual game elements and see exactly how well each one is performing. Polishing even the smallest mechanic can have a drastic impact on the feel of the whole sequence.
Dynamics pertains to the specifics of the mechanics themselves -- how many enemies in a fight, how aggressive the A.I. is, how many shots are fired, how much damage is caused, etc.
There are a couple of terms applied to music that can also be applied to pacing:
- Legato -- long and smooth flowing.
- Staccato - short and detached.
Texture can be used to describe the complexity of what is happening at a given point. A rich texture may be a sequence of gameplay that has many different things happening all at once. However, gameplay with too much complexity can become disordered and unreadable. Sometimes a simple texture can be more pleasing.
There are several musical terms that can be applied:
- Monophony - single notes at a time, or in the case of gameplay, single mechanics used one at a time.
- Homophonic -- using harmonies, such as chords on a single melody. This would be the use of mechanics that work well together in defined patterns.
- Polyphonic -- multiple melodies playing at the same time. This would be extremely complex scenarios in terms of gameplay, where different gameplay elements are occurring in their own patterns. This would be fairly rare without being a complete mess.
- Heterophonic -- the same melody is being played with slight variations at the same time. This is more likely to be workable than a polyphonic scenario, as it would be more readable in terms of what is going on.
Case Study: Call of Duty 4 "All Ghillied Up"
As an example of how pace could be controlled in a game I examined a video of one of the best levels in one of my favorite games. The level is really a master class in forced pacing -- I suspect that most people's playthrough times are very similar -- certainly for earlier parts of the level.
This study examines a small 10 minute section of the beginning of the level, showing how the threat, tension, movement impetus and tempo change quickly over the course of the scenario. The level uses the very clever tactic of a scripted AI buddy to literally drive the pace at every moment during the gameplay. It isn't generally possible to do this in most level designs, but it is a very efficient method of controlling the pace.
Throughout the whole of this 10 minute section the tempo is never extremely high, as there is little in the way of fast paced action until much later in the level, but the pace was maintained constantly by having either threat, tension or movement impetus high at every point.
There are constantly repeating gameplay elements throughout (as there always tends to be in FPS games) -- movement to a point, then waiting before eliminating a threat, returning to movement once complete (which could quite easily be described as Tremolo -- rapid alternation between two mechanics).
0:18 -- Arrival
Movement Impetus: High
- Obstacle up ahead -- "too much radiation we'll have to go around"
- Tells you to follow him -- he is now leading you through the first part of the level, we have forced pacing -- he moves pretty quickly, but gives us information as we move.
0:40 -- First Contact
Movement Impetus: Low
- He stops and the movement impetus slows for a moment, however the pace is still high as there is tension -- they make visual contact with the enemy.
- They now creep slowly ahead; whilst there is forced pacing the movement impetus is low. The perceived threat is high however, so it feels high paced and tense.
- Option is then offered to take out one of the two guards when not looking. This slows the pace right down as the player observes and formulates a plan.
1:29 -- Move Up
Movement Impetus: High
- The target is eliminated; suddenly the obstacle has been cleared. The AI buddy now instructs the player to move, the movement impetus picks up again.
1:40 -- Go Around
Movement Impetus: Medium
- The player is told to "hold up". Suddenly our movement impetus has stopped. Again the tension rises as the perceived danger increases.
- Movement impetus is started again as he instructs them to go around to use more cover, but we have seen the enemy so our perceived threat is now really high.
1:53 -- Four Tangos
Movement Impetus: Low
- A real threat is presented to the player -- four enemies inside a building in extremely close proximity. The perceived danger is very high, but your AI buddy instructs you not to engage.
- Whilst you are engaged in this dilemma another guard approaches outside. You are offered the choice to take him out or let him pass -- again the pace slows as the player takes time to make the decision.
2:15 -- Go
Movement Impetus: High
- Once the threat has been removed then the pace picks up again as the movement impetus is raised yet again by the AI buddy.
- This pace is quite staccato however, as he stops by a set of cover for a moment before continuing.
2:35 -- Guard in the Tower
Movement Impetus: Low
- Again they stop as the AI buddy spots the enemy in the tower and a patrol closing in. This is effectively a timed challenge -- forcing a change of pace and heightening the perceived threat. However the player is forced to make a plan and may take a while to reach a decision.
- Once the guard in the tower is taken out again the pace slows as they have the option to take out the patrolling guard or let him pass.
3:12 -- On the move again
Movement Impetus: High
- Once the obstacle is removed they are again on the move in a staccato fashion.
- Some items near the car slow the player for a moment as he takes a second to decide if he wants to take the items or not.
- They speed up and again slow as they enter the building.
- They move pretty quickly through the building, and the "coast is clear" command increases the movement impetus out into the field beyond.
3:45 -- Helicopter
Movement Impetus: Very Low
- The movement impetus from the previous section is suddenly halted as they reach the gate, as an enemy helicopter passes overhead.
- The perceived threat is however severely raised by this event.
4:06 -- Let's Go
Movement Impetus: High
- Again they are on the move once the threat has disappeared.
- This is now a fairly long section of high movement impetus in comparison to what has been seen previously. It nicely relieves the tension for a moment. However, it turns out to be the calm before the storm.
4:24 -- Enemy Patrol
Threat: Very High
Tension: Very High
Movement Impetus: Very Low
- This tension is suddenly ramped up massively as a large patrolling group of enemies with vehicles heads directly towards them -- emphasized by the dramatic change in music.
- Perceived danger is extremely high as it appears to be certain death if they are spotted.
- Movement impetus is slowed and eventually reduced to virtually nil, as the player formulates their strategy to try and evade the incoming patrol.
- The enemy proximity makes for extremely tense gameplay as they edge ever closer to your position.
- As they move past the tension starts to subside as you realize that they haven't spotted you. The movement impetus to get away from the enemy threat rises dramatically.
6:05 -- Move Slow
Movement Impetus: Medium
- Even though the patrol has passed the movement impetus is kept low as the AI Buddy instructs the player to move slowly.
- There is still a large perceived danger of being spotted.
- Tension starts to fade as you hear the sounds of the patrol moving away behind you.
6:55 -- The Lake
Movement Impetus: Medium
- Again movement impetus is raised as they are now out of visual range. The AI Buddy picks up the tempo as they move onwards, but this is a very short distance before they reach another obstacle.
- They sneak around to another point before stopping. Here the pace is slowed as he offers the player a choice to either take them out or sneak past them.
- The player takes time to decide. If they take the shot the pace is again forced as the AI buddy instructs the player to wait until he gets into position before they take out the next targets.
- Once it is time for the player to take their shot there is again a good period of time in which to make their decision.
8:33 -- Onwards
Movement Impetus: High
- They are on the move again -- having had some pretty slow moving sections this fast movement lasts a little while to give a nice sense of relief.
8:55 -- Stay Back
Movement Impetus: Medium
- Yet again however movement impetus is halted as they move up right behind an enemy in very close proximity. The tension is raised dramatically.
- The pace is forced as the AI buddy declares that he will take out the enemy -- the player will generally wait and watch.
- After a very short section of forward movement he again stops the player instructing them to wait as he moves forwards.
- The tension is increased as he informs the player of a patrol coming their way. They hear the patrol approaching slowly before he is taken out by the AI Buddy.
Pace is talked about a lot in regard to game design, but it is still poorly defined -- searching the internet for relevant topics brings up virtually nothing.
As we develop as an industry we need more critical analysis of our work. Whilst we can easily develop our own terminology and draw our own conclusions, it is worth examining other fields of cultural analysis and apply them to our field.
Perhaps we could even adapt musical notation to some form of written system to define the pacing of a game?
I believe there is plenty more that can be discovered about pacing in games -- certainly some more scientific studies of heart rate, etc whilst playing games might unearth some real revelations about what makes the pace in games so emotionally involving and also what simply does not work.
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