In
the first installment of his series on gameplay, systems and mechanics
fundamentals, systems design veteran Mike Lopez focuses on maximizing
the player experience through the planning, structure and execution of
the key elements of Gameplay Progression (mechanics, duration,
ancillary rewards, practical rewards and difficulty).
Gameplay WHAT?
Most people who play games are probably familiar with the concept of
difficulty progression, at least at a subconscious level - that games
should get harder over time. Most designers presumably know to build
increasing difficulty into successive levels, missions, worlds, or
courses (usually the single player experiences). But difficulty is only
one portion of the overall game experience, and there are several other
elements that need to be structured, managed and revealed carefully in
order to provide the user with a truly compelling and enjoyable
experience throughout gameplay. So, what exactly is Gameplay
Progression?
Progression
n 1: a series with a definite pattern of advance [syn: patterned
advance] 2: a movement forward [syn: progress, advance] 3: the act of moving forward toward a goal [syn: progress, procession, advance,
advancement, forward motion, onward motion]
[ WordNet ® 2.0, © 2003 Princeton University (via dictionary.com) ]
All 3 of these definitions for progression apply to games, because it
is both the realized pattern of advance and the act of movement towards
the ultimate goal (winning the game) that are essential to an enjoyable
experience for the player. The pattern or structure of the advance is
what will ensure a rewarding experience during gameplay and will ensure
the further continuation and replay necessary to turn renters into
buyers.
Key Elements of Gameplay Progression:
- Game Mechanics – all controls and interactions within the game, including new weapons, abilities, powers, vehicles, and environmental states or events.
- Experience Duration – the average time it takes to complete each stage, level, mission (including deaths if applicable) or course (using the most relevant vehicle).
- Ancillary Rewards (visual, aural, decorative, etc.) – exciting environmental wonders, fancy visual effects, scripted events, etc. It is great to weight some of the more spectacular environmental wonders and effects up front (Medal of Honor style), but an enjoyable game needs to have all the level, course or mission experiences built so that new visual rewards are staggered at a pace that keeps the user interested (in other words with an Environmental Progression in mind).
- Practical Rewards (gameplay relevant) – new game modes, upgrades and practical unlockable content are very useful as the carrot on the stick that entices users to continue playing the game.
- Difficulty – not just how hard it is to pass obstacles and NPCs/bosses, but also how much risk is taken with respect to player injury/death, weapon depletion, or vehicle/equipment damage or loss.
Games that do not structure the distribution of all these elements risk the danger of overwhelming the player with too much up front, or they risk not keeping users engaged enough with new elements to keep them playing or to encourage renters to buy. We have all played games that have suffered from sadly common issues like difficulty spikes, frustrating mechanics complexity, or those that we just become bored with after the first few hours – all of which are symptoms of unstructured, ill-designed and/or un-managed game progression.
One of the reasons many Nintendo games are considered a bench mark for quality is that games like Zelda
have the most meticulously planned, structured and executed gameplay
progressions of any games on the market, and on a subconscious level
the experience in those games feels just right for players in terms of
increasing challenge, complexity, risk and reward. In fact, a truly
engaging and memorable player experience is one where all the above
elements of progression are carefully laid out and then the gameplay
content (levels, missions or courses) is built to fit within that
structure such that the pace of new elements is controlled and somewhat
predictable, yet always keeps the player wanting more.
Game Mechanics
Game mechanics are an extremely important segment of gameplay because
they directly affect the control complexity and in turn the learning
curve. For a simple game with limited mechanics (say an arcade racer
with only steer, throttle and brake) a designer need not layer in the
mechanics. But, for a more complex game (Halo, Splinter Cell, Zelda, Ratchet & Clank), mechanics progression is essential so as not to overwhelm the player with the complexity of the controls.
The 2 main styles of mechanics progression that can be used in games
with even a moderate level of mechanics complexity are what I call
Gated Access and Directed Gameplay:
- Gated Access – make some mechanics unavailable initially until a later point in the game (via inventory, disabled controls that later get enabled, or progressively adding in new moves, etc.).
- Directed Gameplay – make all mechanics available up front but direct the gameplay (missions or levels) to utilize mechanics progressively (so the first levels only require the basics and each level or stage layers on something new).
Some games use one or the other and some use both (Halo for instance requires more skill with the mechanics later on and opens new weapons and vehicles to be acquired / used).
Weapons or any inventoried mechanics are an obvious segment to reveal progressively via Gated Access. The best combat games actually reveal a new weapon sooner than they make that weapon consistently available to the player (for example an enemy may have a new weapon, and you can kill them to get it, but only with a limited supply of ammo up front). Deeper driving games should manage the progression of mechanics by directing the gameplay to control when more complex mechanics must be used and at what frequency (see Fig 1).
The thing to remember is that most any game in any genre (maybe other
than team sports) can and should have their mechanics structured as
part of the gameplay progression in order to deliver a great experience
for the player (easy to grasp, keeping the user wanting more, and
rewarding continuation with new abilities and/or new challenges).
Experience Duration
Not all games have to increase the length of the experience to be fun or successful, but experience length can directly support the gameplay progression and in turn the overall enjoyment of the experience. In all 8 Road Rash versions I worked on, we made sure to increase the length of races (both in distance and in time) at every level, and although it was a subconscious decision at the time, I now recognize that approach as a part of the gameplay experience progression. Racing games have to increase the race length more on new level races since presumably they also have faster vehicles on the new level (which can cover more ground in the same time). Combat games can increase in mission distance, opponent difficulty and penalty (e.g. player death) to increase the overall experience time.


Some platform games have very short levels at the start (teaching basic mechanics) and then longer levels farther in. Even subtle differences in experience length over time will subconsciously increase the sense of progress for the user and therefore their overall gratification (ask most players why Zelda games are so excellent and they may be hard pressed to articulate the reasons, because the feel of the experience is such a subjective thing, but much of that cohesive feel is delivered via gameplay progression).
On a micro level, the user should also feel a sense of progression within a single mission, level or course and the building structure into the content allows the designers to control the pacing, and gradually increase the intensity within a single level, race or mission. On a macro level, the sense of advancement and overall game percentage completion for the player should be obvious.
Ancillary Rewards & Environmental Progression
Most games are filled with pleasing rewards that do not directly affect
how the user plays the game, but ancillary rewards (visual, aural or
decorative) add to player gratification and therefore encourage
replayability. Visual environmental rewards can be very pleasing and
memorable to the player and include things like fantastic environments,
amazing particle or lighting effects, and incredible scripted action
events (e.g. Medal of Honor and Call of Duty style) and an Environmental Progression
of these elements is therefore an extremely important area to plan and
structure since it is key to encouraging continuation and replay.
Environmental rewards are especially valuable to the player experience
since they can directly affect the gameplay pacing and so they should
occur fairly often (usually one at a time) within a level, mission or
race.
Decorative rewards can be things like Trophies or Medals (Medal of Honor)
that serve as unlocked collectibles but do not alter the gameplay.
Decorative Rewards do add value in helping recognize player progress,
but in this day and age a game that entirely substitutes Practical
Awards with Ancillary rewards will often get hammered in chat forums
and in review scores.
Key visual rewards
that dramatically affect the pace of gameplay and thus need to be
designed and structured into an Environmental Progression
are things like scripted action events, the intensity of those action
events, visual wonders, landmarks (essential for proper navigation and
orientation), object groups, terrain types, and weather types (see Fig 4).
The original Medal of Honor did an excellent job of progressively structuring the unlockable medals, and since this was pretty new to FPS console gamers at the time (around 1999), these Decorative Ancillary Rewards were extremely effective as an incentive for replay (gamers just had to earn those medals). If Decorative Ancillary Rewards are the bulk of the unlockable content the first unlockables should be revealed quickly and then over progressively longer time periods from that point. Care should also be taken to make Ancillary Rewards interesting and unique enough to keep players interested (generic bronze, silver, and gold trophies or medals are less likely to satiate players in this day and age).
Ancillary rewards can also help dramatically play up key game events. For Road Rash: Jailbreak,
we reinforced the combat knock-down with visual and audio rewards
(skull & bones icon and cash register sound effect) to make it more
gratifying. Team skeptics (myself included) quickly changed their tune
when those audio/visual rewards were proven to have increased the
gratification of knock-downs during focus tests. The point here is that
key game mechanics or systems should be the first place to consider
adding visual and audio rewards, but in that case, there is no
progressive gameplay structure and those portions of ancillary rewards
will not directly enhance the overall gameplay progression. In fact, in
order to maximize gameplay continuation and replay many other Ancillary
Rewards (e.g. scripted action events, environmental wonders, and other
visual rewards) can and should be structured into an Environmental Progression Plan prior to having those levels, or areas constructed by the artists and/or level designers (see Fig 4 above);
ensuring successive levels or missions have an interesting new mix of
action and visuals will serve the dual purpose of rewarding prior
player progress and enticing their continuation and replay.
Practical Gameplay Rewards
More and more games these days are following the old-school RPG and
fighting game model of unlocking practical new content pieces that
directly change, expand or improve the way the game is played. Fighting
games may unlock new characters, attacks or powers, while racing games
may unlock new vehicles, vehicle upgrades or race courses and combat
games unlock new weapons, multiplayer maps, or environments. The reason
more attention is being paid to rewards these days is that players have
come to expect them in many instances, but also that practical gameplay
rewards lead the player through the game and are the most effective
means to encourage continuation and replay (vs. decorative rewards or
just beating the game). An excellent example of structured practical
rewards in my opinion is in Burnout: Revenge,
where new modes, new tracks and new vehicles are all unlocked at a
structured pace (the rate seems fast at the start and progressively
slower through the game), with a few nice awards very soon after
starting the game. A well planned and executed practical reward
structure is extremely helpful in enticing player continuation and
replay and ultimately in increasing review scores.
It is extremely important that the player be able to understand the
rewards system. Some games present rewards just after completing a
level, while others award money at the end of the mission, race or
level and then allow the user to purchase new content, and in these
cases the rewards system needs little or no explanation. Other games
tabulate experience points or other categories which either
automatically unlock the reward at a predefined pace, or allow the user
to select which reward they wish to purchase; either way these systems
of points need to be explained more clearly (or at least presented with
the reward input / output organized in a table) since they are not as
intuitive. For a combat game like any of the James Bond or Medal of Honor games,
the mission results screens usually tabulate categories like shot
accuracy, remaining health, enemy kills, or enemies escaped, and in any
such game there should be a point value associated with the performance
in each category that serves as a system explanation, because the user
can see the relative weights of each category (see Figures 5a/b for some fictional mission results examples);
a player can use the category information and relative values in their
future gameplay strategy in order to improve their ability to earn
rewards. Keeping the system as obvious and simple as possible will
reduce the amount of explanation feedback the interface will need to
provide.
Ideally, the player should also get a glimpse at the rewards content that lies ahead (either the next few or all remaining practical rewards) in order to encourage their long-term continuation and replay. It is great to know the next reward (say a key character model unlocked for play in multiplayer). It is even better if the player can see that mysterious and intriguing new team gameplay mode or crazy character or weapon that is available several awards down the line (see Fig 6) because they might want that one so bad they will extend their play in the current sitting or at least keep playing long after they might otherwise, just to gain that item and be able to experience it in gameplay.
These days it is increasingly more
important that the main content unlocking system of the game feature
Practical Gameplay rewards only. Decorative Ancillary Rewards
(Trophies, etc.) do add value but should be presented separately from
Practical Rewards; if it appears that Decorative Rewards are stuck into
the system to fluff up the appearance of Practical Rewards then the
chat forums and reviewers may respond with comments like some of them
are ‘useless’ or ‘cheap’. Decorative Rewards can supplement the
Practical Rewards, but they should be kept separate and not treated as
equals.
Difficulty
Most
non-sports games have some sort of difficulty progression, but often it
is unstructured, unplanned or ill-defined and this results in
difficulty spikes, early frustration (too much challenge), or possibly
early game abandonment (players get bored from not enough new
challenge). A developer challenge for properly structured difficulty
progression is to be far enough into development to completely
understand the elements that affect difficulty the most (e.g. weapons,
single enemy offensive/defensive behaviors, group behaviors, enemy
class strengths, and enemy class quantity and group distribution), and
yet still early enough to give your team time to refine the tuning of
the content (levels, missions or courses) to fit the desired difficulty
progression and especially to verify that progression with external
subjects (focus testers, etc.).

An example of a
Curved Difficulty Progression
The best structured games start out extremely easy to allow all players to quickly experience the reward of game progress (by completing the level, winning the race, or defeating the opponent). A game can have a linear progression where each successive level, stage, or mission is designed to take an even step in difficulty and the magnitude of that step stays consistent over time. However, the problem with a linear difficulty progression is that it may frustrate casual gamers too soon (say by level 3 or 4) and since most designers should want to make mass market games these days that is a demographic we cannot afford to alienate (we do want those renters to buy, right?).
A curved difficulty progression can often be the best, since it allows for casual gamers to get a reasonable distance into the game, and hard core players will breeze past the first few levels, but the levels then start to increase progressively in difficulty (each step is greater than the last) to continually test their skill and their ability to adapt to the new mix of challenges. As systems designers, we have to figure out how to plan and structure our game difficulty and at a high level a first step is to estimate how often the player will die (see Fig 7), wreck their vehicle, or fail a challenge. From there all categories that affect the estimated failure rate should be added to the difficulty progression table and the table must be followed for the levels, missions or courses as they are built. Finally, the difficulty progression must be verified and tuned via focus testing.
The Challenge
Often the real development challenge is not in knowing how to structure
a great and engaging game progression, but in how to steer a large
portion of the development team to achieve it. It is one thing for the
lead designer to be able to tune or direct all the difficulty balancing
of the gameplay on a game with limited systems, but it is a much more
difficult and costly maneuver to attempt to steer multiple level
designers, effects artists, world builders, and AI programmers to
achieve a wider and more desirable gameplay progression on a more
complex game. Ideally, the progression is designed and planned early
enough to bring the producer and team leads on board into backing such
an approach, but on first generation engines often certain elements
remain unknown until deep into production (e.g. how different AI
behaviors affect difficulty). So, it is best to both plan the
progression in advance as much as possible (early production), and to
set a planned checkpoint later on to update the progression structure
with formerly unknown elements, and finally to set multiple review and
feedback loops in the content to make sure the progression structure is
supported, followed and satisfactory to focus testers.
I admit to not having yet personally achieved the perfect
gameplay progression execution on the games I have designed systems and
mechanics for, and I am not sure I can say for sure if I ever will. But
in my 15 years of design experience I have learned to identify the
progression patterns in top-quality games, and that experience has led
me to consciously plan the progression structure much more thoroughly
than I used to, and I have strived to work within my influence and
abilities to execute content to that structure as much as possible.
Each development experience has led to more process learning on my part
and, as an external Creative Manager, I now heavily encourage all the
design teams I am working with to structure the gameplay progression
early on and to build content that fits that structure from the start.
Realistically, the goal for us game designers should not be to build a
Nintendo-worthy gameplay experience (it has taken them 20 years to get
there), but to build the most enjoyable experience for the specific
game we are working on and ultimately to make our users excited enough
to play (and buy) our game. Then all will be right in the [game] world
and [hopefully] the peasants will rejoice. M’kay?