A Look at Puzzle Games

In this article, game designer Sande Chen reflects on the level design of puzzle games and how allowing the player to win can help in the success of the game.

One year, at the Austin Game Conference, I was exhausted, not from partying, but because I had stayed up all night trying to progress through Puzzle Bobble.  My college friend had the original arcade machine and since I could use the same quarter over and over, I stayed with it.  I noticed almost immediately spikes in difficulty, remarking how I felt that one level was out of place because it was especially hard and the levels after it were easy in comparison.  Considering that the player also gains proficiency, gauging the increase in difficulty or challenge between levels must be an interesting exercise. 

Photo Credit: Andrés Álvarez Iglesias

In addition, there is a luck variable to these puzzles since colors can randomly get scarce on you.  It's the same way with Candy Crush Saga, that when you need red candies, you feel like all the other colors keep on showing up.  I especially hate using up moves while waiting for a certain color to show up in a line.  This probably contributed to my decision to delete Blossom Blast Saga.

I mean, I do have a certain amount of patience with difficult puzzles and in most free-to-play games, a player may have access to power-ups or boosters that can make uneven level design tolerable, but when my puzzle-solving efforts feel like frustration rather than fun, then I'll just quit.  Especially when I feel like it's a luck-related factor.

Candy Crush Saga showers me with free gifts, but that's not the only reason why I still play Candy Crush.  I fully realize Candy Crush Saga has that luck component but despite that, I still manage to have fun with it.  The way the levels are designed, I always feel like I have a chance at solving the puzzle because I'll be one or two moves out.  That motivates me to keep on playing because sooner or later, I'll feel like I'll solve it, even if it takes a long time.  If I don't see that possibility of winning, then I'll throw my hands figuratively in the air and mutter, "This is impossible!"  I can see why players are motivated to buy extra moves because it's almost ... just almost... there.  Unlike with Candy Crush Jelly Saga, another I deleted, I did have those boosters in Candy Crush Saga, so if I did feel like I had come across an impossible level, I could help myself out.

I also play Candy Crush Soda Saga, which I like better, even though there aren't free boosters given out there.  I've noticed that after I've been at a puzzle for a long time on Candy Crush Saga, something remarkable will happen such as a color ball and a color bomb ending up next to each other.  I have no idea if that was just the allotted time needed for this lucky occurrence to happen or if the designers were specifically thinking about helping me along.  It would be great if this were a matter of design.

In the past, I was in charge of designing a mah jong solitaire game.  In those types of games, there are the ones where it's possible for the player to have a puzzle without a solution. Alternately, there are the ones that use an algorithm to make sure there was always a solution to the puzzle.  I suppose in the former, a player would be able to get out of that unsolvable state with a booster.  I chose the latter because I always wanted players to be able to win without using boosters.  It seems unfair that the player could be presented with a puzzle that couldn't be solved without a booster.  After all, I wanted the player to stick around for the next level or game.

Challenge is great, but too much challenge leads to frustration, which can lose players.

Sande Chen is a writer and game designer whose work has spanned 10 years in the industry. Her credits include 1999 IGF winner Terminus, 2007 PC RPG of the Year The Witcher, and Wizard 101. She is one of the founding members of the IGDA Game Design SIG.

Player vs. Designer: Tracking User Experience

In this article, game designer Sande Chen gives advice on how to interpret player feedback and how it impacts user experience.

Have you heard the advice, "Take the note under the note"?  As a young screenwriter, I found this advice baffling, especially when in my first Hollywood meeting, the director said one thing and then the producer completely contradicted the director, asking for a rewrite that I thought was impossible if I followed the director's wishes.  Yet, they were smiling in agreement, seemingly both on the same page.  What the heck was going on?  Life would be much simpler if there were a feedback interpreter at every meeting.      

The problem with feedback is that not everyone can clearly enunciate what is wrong.  Moreover, people may be just bad at giving feedback.  They can only tell you what they felt when they went through the material while you fight back the urge to point out that if only they had read this section, they would understand everything.  The thing is, if they missed that section, that's feedback in itself.  What's important is not the actual words in the feedback, but what you can interpret about the user experience.

Last week at the 2015 New York Comic Con Livestream panel, Writing for Video Games, which was broadcast on Twitch, I eluded to this topic when asked about how to deal with player feedback.  I described a situation whereby designers reacted to player feedback in a MMO and then ended up making the situation worse. 

Matthew Weise, Caitlin Burns, Sande Chen, Steele Filipek at NYCC

In this example, the player response to this MMO world was loud and critical.  The whole thing was too boring.  Too many talk-to quests and not much killing.  I could see that the writer(s) were trying to develop a story, but not many players found the story interesting, especially when they wanted to kill something.  You could blame the players, but the fact is, in a kill-centric MMO, players want to kill.  It's not a MMO about diplomacy.

The designers took that note and in the next release, changed tactics.  Now, there were very few talk-to quests and lots of Kill-10, Kill-Collect, and boss fights.  It was Kill, Kill, Kill.  But the players were more upset than ever because bottlenecks were appearing everywhere.  Players complained that they had to kill hundreds of these mobs and how it was so boring to kill the same thing over and over.  What happened?

Now, you might interpret this feedback as players complaining about everything.  They complained about story quests and then they complained about kill quests.  It might seem that way, but let's examine that first note more closely.  Instead of taking the feedback at face value and replacing all the story quests with kill quests, the designers might have realized that this was an issue of pacing.  Story quests aren't evil.  Neither are kill quests.  They're just part of the user experience.

In this day and age, we're lucky that we can get player feedback so quickly.  This relationship doesn't have to be adversarial.  There's no right or wrong in how somebody feels.  However, we do have to develop a filter to interpret the feedback.  Zeroing in on the user experience is one way of putting player feedback in focus.

Sande Chen is a writer and game designer whose work has spanned 10 years in the industry. Her credits include 1999 IGF winner Terminus, 2007 PC RPG of the Year The Witcher, and Wizard 101. She is one of the founding members of the IGDA Game Design SIG.

IGDA Webinar: Constructing Ramped Difficulty in Gameplay

In this video, game designer Michael John of GlassLab discusses the concept of flow in macro design and how it relates to difficulty and engagement. 
 

Game design Webinars from the IGDA are held on every third Wednesday of the month.

IGDA Webinar: The Evolution of Videogame Design

In this video, creative producer Patrick Holleman describes how tenets of game design evolved during the three historical ages that he calls the arcade era, the composite era and the set piece era.

Game design Webinars from the IGDA are held on every third Wednesday of the month.

Advancement, Progression and Pacing (Part V)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games. In Part II, he discusses challenge levels in PvE.  In Part III, he explains how to handle the reward schedule in PvE.  In Part IV, he tackles challenge levels in PvP. In the final segment, he discusses the relationship between difficulty levels and pacing.

Flow Theory, Revisited 

With all that said, let’s come back to flow. There were two problems here that needed to be solved. One is that the player skill is increasing throughout the game, which tends to shift them from being in the flow to being bored. This is mostly a problem for longer PvE games, where the player has enough time and experience in the game to genuinely get better.

The solution, as we’ve seen when we talked about PvE games, is to have the game compensate by increasing its difficulty through play in order to make the game seem more challenging – this is the essence of what designers mean when they talk about a game’s “pacing.” For PvP games, in most cases we want the better player to win, so this isn’t seen as much of a problem; however, for games where we want the less-skilled player to have a chance and the highly-skilled player to still be challenged, we can implement negative feedback loops and randomness to give an extra edge to the player who is behind.

There was another problem with flow in that you can design your game at one level of difficulty, but players come to your game with a range of initial difficulty levels, and what’s easy for one player is hard for another.

With PvE games, as you might guess, the de facto standard is to implement a series of difficulty levels, with higher levels granting the AI power-based bonuses or giving the player fewer power-based bonuses, because that is relatively cheap and easy to design and implement. However, I have two cautions here:

1. If you keep using the same playtesters, they will become experts at the game, and thus unable to accurately judge the true difficulty of “easy mode”; easy should mean easy and it’s better to err on the side of making it too easy, than making it challenging enough that some players will feel like they just can’t play at all. 
2. Take care to set player expectations up front about higher difficulties, especially if the AI actually cheats. If the game pretends on the surface to be a fair opponent that just gets harder because it is more skilled, and then players find out that it’s actually peeking at information that’s supposed to be hidden, it can be frustrating. If you’re clear that the AI is cheating and the player chooses that difficulty level anyway, there are less hurt feelings: the player is expecting an unfair challenge and the whole point is to beat that challenge anyway. Sometimes this is as simple as choosing a creative name for your highest difficulty level, like “Insane.”

There are, of course, other ways to deal with differing player skill levels. Higher difficulty levels can actually increase the skill challenge of the game instead of the power challenge. Giving enemies a higher degree of AI, as I said before, is expensive but can be really impressive if pulled off correctly. A cheaper way to do this in some games is simply to modify the design of your levels by blocking off easier alternate paths, forcing the player to go through a harder path to get to the same end location when they’re playing at higher difficulty.

Then there’s Dynamic Difficulty Adjustment (DDA), which is a specialized type of negative feedback loop where the game tries to figure out how the player is doing and then adjusts the difficulty on the fly. You have to be very careful with this, as with all negative feedback loops, because it does punish the player for doing well and some players will not appreciate that if it isn’t set up as an expectation ahead of time.

Another way to do this is to split the difference, by offering dynamic difficulty changes under player control. Like DDA, try to figure out how the player is doing… but then, give the player the option of changing the difficulty level manually. One example of this is the game flOw, where the player can go to the next more challenging level or the previous easier level at just about any time, based on how confident they are in their skills. Another example, God of War did this and probably some other games as well, is if you die enough times on a level it’ll offer you the chance to drop the difficulty on the reload screen (which some players might find patronizing, but on the other hand it also gives the player no excuse if they die again anyway). Sid Meier’s Pirates actually gives the player the chance to increase the difficulty when they come into port after a successful mission, and actually gives the player an incentive: a higher percentage of the booty on future missions if they succeed.

The equivalent in PvP games is a handicapping system, where one player can start with more power or earn more power over the course of the game, to compensate for their lower level of skill. In most cases this should be voluntary, though; players entering a PvP contest typically expect the game to be fair by default.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.  

Advancement, Progression and Pacing (Part IV)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games. In Part II, he discusses challenge levels in PvE.  In Part III, he explains how to handle the reward schedule in PvE.  Next, he tackles challenge levels in PvP.

Challenge Levels in PvP 

 If PvE games are all about progression and rewards, PvP games are about gains and losses relative to your opponents. Either directly or indirectly, the goal is to gain enough power to win the game, and there is some kind of tug-of-war between the players as each is trying to get there first. I’ll remind you that when I’m saying “power” in the context of progression, I’m talking about the sum of all aspects of the player’s position in the game, so this includes having more pieces and cards put into play, more resources, better board position, taking more turns or actions, or really anything that affects the player’s standing (other than the player’s skill level at playing the game). The victory condition for the game is sometimes to reach a certain level of power directly; sometimes it is indirect, where the actual condition is something abstract like Victory Points, and it is the player’s power in the game that merely enables them to score those Victory Points. And in some cases the players don’t gain power, they lose power, and the object of the game is to get the opponent(s) to run out first. In any case, gaining power relative to your opponents is usually an important player goal.

Tracking player power as the game progresses (that is, seeing how power changes over time in a real-time game, or how it changes each turn in a turn-based game) can follow a lot of different patterns in PvP games. In PvE you almost always see an increase in absolute player power level over time (even if their power level relative to the challenges around them may increase or decrease, depending on the game). In PvP, there are more options to play with, since everything is relative to the opponents and not compared with some absolute “You must be THIS GOOD to win the game” yardstick.

Positive-sum, negative-sum, and zero-sum games

Here is an important distinction in power-based progression that we borrow from the field of Game Theory: whether the game is zero-sum, positive-sum, or negative-sum. If you haven’t heard these terms before:

• Positive-sum means that the overall power in the game increases over time. Settlers of Catan is an example of a positive-sum game: With each roll of the dice, resources are generated for the players, and all players can gain power simultaneously without any of their opponents losing power. Monopoly is another example of a positive-sum game, because on average every trip around the board will give the player $200 (and that money comes from the bank, not from other players). While there are a few spaces that remove wealth from the game and are therefore negative-sum (Income Tax, Luxury Tax, a few of the Chance and Community Chest cards, unmortgaging properties, and sometimes Jail), on average these losses add up to less than $200, so on average more wealth is created than removed over time. Some players use house rules that give jackpots on Free Parking or landing exactly on Go, which make the game even more positive-sum. While you can lose lots of money to other players by landing on their properties, that activity itself is zero-sum (one player is losing money, another player is gaining the exact same amount). This helps explain why Monopoly feels to most people like it takes forever: it’s a positive-sum game so the average wealth of players is increasing over time, but the object of the game is to bankrupt your opponents which can only be done through zero-sum methods. And the house rules most people play with just increase the positive-sum nature of the game, making the problem worse!

• Zero-sum means that the sum of all power in the game is a constant, and can neither be created nor destroyed by players. In other words, the only way for me to gain power is to take it from another player, and I gain exactly as much as they lose. Poker is an example of a zero-sum game, because the only way to win money is to take it from other players, and you win exactly as much as the total that everyone else loses. (If you play in a casino or online where the House takes a percentage of each pot, it actually becomes a negative-sum game for the players.)

• Negative-sum means that over time, players actually lose more power than they gain; player actions remove power from the game without replacing it. Chess is a good example of a negative-sum game; generally over time, your force is getting smaller. Capturing your opponent’s pieces does not give those pieces to you, it removes them from the board. Chess has no zero-sum elements, where capturing an enemy piece gives that piece to you (although the related game Shogi does work this way, and has extremely different play dynamics as a result). Chess does have one positive-sum element, pawn promotion, but that generally happens rarely and only in the end game, and serves the important purpose of adding a positive feedback loop to bring the game to a close.

An interesting property here is that changes in player power, whether zero-sum, positive-sum, or negative-sum, are the primary rewards in a PvP game. The player feels rewarded because they have gained power relative to their opponents, so they feel like they have a better chance of winning after making a particularly good move.

Positive and negative feedback loops

Another thing I should mention here is how positive and negative feedback loops fit in with this, because you can have either kind of feedback loop with a zero-sum, positive-sum or negative-sum game, but they work differently. In case you’re not familiar with these terms, “positive feedback loop” means that receiving a power reward makes it more likely that you’ll receive more, in other words it rewards you for doing well and punishes you for doing poorly; “negative feedback loop” is the opposite, where receiving a power reward makes it less likely you’ll receive more, so it punishes you for doing well and rewards you for doing poorly.

One interesting property of feedback loops is how they affect the player’s power curve. With negative feedback, the power curve of one player usually depends on their opponent’s power: they will increase more when behind, and decrease more when ahead, so a single player’s power curve can look very different depending on how they’re doing relative to their opponents, and this will look different from game to game.

With positive feedback, you tend to have a curve that gets more sharply increasing or decreasing over time, with larger swings in the endgame; unlike negative feedback, a positive feedback curve doesn’t always take the opponent’s standings into account… it can just reward a player’s absolute power.
Now, these aren’t hard-and-fast rules… a negative feedback loop can be absolute, which basically forces everyone to slow down around the time they reach the end game; and a positive feedback loop can be relative, where you gain power when you’re in the lead. However, if we understand the game design purpose that is served by feedback loops, we’ll see why positive feedback is usually independent of the opponents, while negative feedback is usually dependent.

The purpose of feedback loops in game design

The primary purpose of positive feedback is to get the game to end quickly. Once a winner has been decided and a player is too far ahead, you don’t want to drag it out because that wastes everyone’s time. Because of this, you want all players on an accelerating curve in the end game. It doesn’t really matter who is ahead; the purpose is to get the game to end, and as long as everyone gets more power, it will end faster.

By contrast, the primary purpose of negative feedback is to let players who are behind catch up, so that no one ever feels like they are in a position where they can’t possibly win. If everyone is slowed down in exactly the same fashion in the endgame, that doesn’t fulfill this purpose; someone who was behind at the beginning can still be behind at the end, and even though the gap appears to close, they are slowed down as much as anyone else. In order to truly allow those who are behind to catch up, the game has to be able to tell the difference between someone who is behind and someone who is ahead.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.  

Advancement, Progression and Pacing (Part III)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games. In Part II, he discusses challenge levels in PvE.  In Part III, he explains how to handle the reward schedule in PvE.

Rewards in PvE 

In PvE games especially, progression is strongly related to what is sometimes called the “reward schedule” or “risk/reward cycle.” The idea is that you don’t just want the player to progress, you want them to feel like they are being rewarded for playing well. In a sense, you can think of progression as a reward itself: as the player continues in the game and demonstrates mastery, the ability to progress through the game shows the player they are doing well and reinforces that they’re a good player.

One corollary here is that you do need to make sure the player notices you’re rewarding them. Another corollary is that timing is important when handing out rewards:

•  Giving too few rewards, or spacing them out for too long so that the player goes for long stretches without feeling any sense of progression, is usually a bad thing. The player is demoralized and may start to feel like if they aren’t making progress, they’re playing the game wrong (even if they’re really doing fine).
• Ironically, giving too many rewards can also be hazardous. One of the things we’ve learned from psychology is that happiness comes from experiencing some kind of gain or improvement, so many little gains produce a lot more happiness than one big gain, even if they add up to the same thing. Giving too many big rewards in a small space of time diminishes their impact. 
• Another thing we know from psychology is that a random reward schedule is more powerful than a fixed schedule. This does not mean that the rewards themselves should be arbitrary; they should be linked to the player’s progress through the game, and they should happen as a direct result of what the player did, so that the player feels a sense of accomplishment. It is far more powerful to reward the player because of their deliberate action in the game, than to reward them for something they didn’t know about and weren’t even trying for. 

There are three kinds of rewards that all relate to progression: increasing player power, level transitions, and story progression.  

Rewarding the player with increased power

Progression through getting a new toy/object/capability that actually increases player options is another special milestone. Like we said before, you want these spaced out, though a lot of times I see the player get all the cool toys in the first third or half of the game and then spend the rest of the game finding new and interesting ways to use them.

Still, if you give the player access to everything early on, you need to use other kinds of rewards to keep them engaged through the longer final parts of the game where they don’t find any new toys. How can you do this?

Here’s a few ways:

• If your mechanics have a lot of depth, you can just present unique combinations of things to the player to keep them challenged and engaged. (This is really hard to do in practice.) 
• Use other rewards more liberally after you shut off the new toys: more story, more stat increases, more frequent boss fights or level transitions. You can also offer upgrades to their toys, although it’s debatable whether you can think of an “upgrade” as just another way of saying “new toy.”
•  Or you can, you know, make your game shorter. In this day and age, thankfully, there’s no shame in this. Portal and Braid are both well-known for two things: being really great games, and being short. 

Rewarding the player with level transitions

Progression through level transitions – that is, progression to a new area – is a special kind of reward, because it makes the player feel like they’re moving ahead (and they are!). You want these spaced out a bit so the player isn’t so overwhelmed by changes that they feel like the whole game is always moving ahead without them; a rule of thumb is to offer new levels or areas on a slightly increasing curve, where each level takes a little bit longer than the last. This makes the player feel like they are moving ahead more rapidly at the start of the game when they haven’t become as emotionally invested in the outcome.  A player can tolerate slightly longer stretches between transitions near the end of the game, especially if they are being led up to a huge plot point. 

Rewarding the player with story progression

Progression through plot advancement is interesting to analyze, because in so many ways the story is separate from the gameplay: in most games, knowing the characters’ motivations or their feelings towards each other has absolutely no meaning when you’re dealing with things like combat mechanics. And yet, in many games, story progression is one of the rewards built into the reward cycle.

Additionally, the story itself has a “difficulty” of sorts (we call it “dramatic tension”), so another thing to consider in story-based games is whether the dramatic tension of the story overlaps well with the overall difficulty of the game. Many games do not: the story climax is at the end, but the hardest part of the game is in the middle somewhere, before you find an uber-powerful weapon that makes the rest of the game easy. In general, you want rising tension in your story while the difficulty curve is increasing, dramatic climaxes at the hardest part, and so on; this makes the story feel more integrated with the mechanics, all thanks to game balance and math.

Combining the types of rewards into a single reward schedule

Note that a reward is a reward, so you don’t just want to space each category of rewards out individually, but also interweave them. In other words, you don’t need to have too many overlaps, where you have a level transition, plot advancement, and a power level increase all at once.

Level transitions are fixed, so you tend to see the power rewards sprinkled throughout the levels as rewards between transitions. Strangely, in practice, a lot of plot advancement tends to happen at the same time as level transitions, which might be a missed opportunity. Some games take the chance to add some back story in the middle of levels, in areas that are otherwise uninteresting… although then the danger is that the player is getting a reward arbitrarily when they feel like they weren’t doing anything except walking around and exploring. A common design pattern I see in this case is to split the difference by scripting the plot advancement so it immediately follows a fight of some kind. Even if it’s a relatively easy fight, if it’s one that’s scripted, the reward of revealing some additional story immediately after can make the player feel like they earned it.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry. 

Advancement, Progression and Pacing (Part II)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games. In Part II, he discusses challenge levels in PvE.

Two Types of Progression 

Progression tends to work differently in PvP games compared to PvE games. In PvP (this includes multi-player PvP like “deathmatch” and also single-player games played against AI opponents), you’re trying to win against another player, human or AI, so the meaning of your progression is relative to the progression of your opponents.

In PvE games (this includes both single-player games and multi-player co-op) you are progressing through the game to try to overcome a challenge and reach some kind of end state, so for most of these games your progress is seen in absolute terms.

Challenge Levels in PvE 

When you’re progressing through a bunch of challenges within a game, how do you track the level of challenge that the player is feeling, so you know if it’s increasing too quickly or too slowly, and whether the total challenge level is just right?

This is actually a tricky question to answer, because the “difficulty” felt by the player is not made up of just one thing here, it’s actually a combination of four things, but the player experiences it only as a single “am I being challenged?” feeling. If we’re trying to measure the player perception of how challenged they are, it’s like if the dashboard of your car took the gas, current speed, and engine RPMs and multiplied them all together to get a single “happiness” rating, and you only had this one number to look at to try to figure out what was causing it to go up or down.

The four components of perceived difficulty

First of all, there’s the level of the player’s skill at the game. The more skilled the player is at the game, the easier the challenges will seem, regardless of anything else.

Second, there’s the player’s power level in the game. Even if the player isn’t very good at the game, doubling their Hit Points will still keep them alive longer, increasing their Attack stat will let them kill things more effectively, giving them a Hook Shot lets them reach new places they couldn’t before, and so on.

Third and fourth, there’s the flip side of both of these, which are how the game creates challenges for the player. The game can create skill-based challenges which require the player to gain a greater amount of skill in the game, for example by introducing new enemies with better AI that make them harder to hit. Or it can provide power-based challenges, by increasing the hit points or attack power or other stats of the enemies in the game (or just adding more enemies in an area) without actually making the enemies any more skilled.

Skill and power are interchangeable

You can substitute skill and power, to an extent, either on the player side or the challenge side. We do this all the time on the challenge side, adding extra hit points or resource generation or otherwise just using the same AI but inflating the numbers, and expecting that the player will need to either get better stats themselves or show a higher level of skill in order to compensate. Or a player who finds a game too easy can challenge themselves by not finding all of the power-ups in a game, giving themselves less power and relying on their high level of skill to make up for it (I’m sure at least some of you have tried beating the original Zelda with just the wooden sword, to see if it could be done). Creating a stronger AI to challenge the player is a lot harder and more expensive, so very few games do that (although the results tend to be spectacular when they do – I’m thinking of Gunstar Heroes as the prototypical example).

At any rate, we can think of the challenge level as the sum of the player’s skill and power, subtracted from the game’s skill challenges and power challenges. This difference gives us the player’s perceived level of difficulty. So, when any one of these things changes, the player will feel the game get harder or easier.

Written mathematically, we have this equation:

PerceivedDifficulty = (SkillChallenge + PowerChallenge) – (PlayerSkill + PlayerPower)

Example: perceived challenge decreases naturally

How do we use this information? Let’s take the player’s skill, which generally increases over time. That’s significant, because it means that if everything else is equal, that is, if the player’s power level, and the overall challenge in the game stay the same, over time the player will feel like the game is getting easier, and eventually it’ll be too easy. To keep the player’s attention once they get better, every game must get harder in some way. (Or at least, every game where the player’s skill can increase. There are some games with no skill component at all, and those are exempted here.)

Measuring the components of perceived challenge

Player skill is hard to measure mathematically on its own, because as I said earlier, it is combined with player power in any game that includes both. For now, I can say that the best way to get a handle on this is to use playtesting and metrics: for example looking at how often players die or are otherwise set back, where these failures happen, how long it takes players to get through a level the first time they encounter it, and so on.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.

Advancement, Progression and Pacing (Part I)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games.

A lot of games feature some kind of advancement and pacing, even multiplayer games. There’s multiplayer co-op games, like the tabletop RPG Dungeons & Dragons or the console action-RPG Baldur’s Gate: Dark Alliance or the PC game Left 4 Dead. Even within multiplayer competitive games, some of them have the players progressing and getting more powerful during play: players get more lands and cast more powerful spells as a game of Magic: the Gathering progresses, while players field more powerful units in the late game of Starcraft. Then there are MMOs like World of Warcraft that clearly have progression built in as a core mechanic of the game, even on PvP servers. So in addition to single-player experiences like your typical Final Fantasy game, we’ll be talking about these other things too: basically, how do you balance progression mechanics?

Wait, What’s Balance Again?

First, it’s worth a reminder of what “balance” even means in this context. In terms of progression, there are three things to consider:

1.  Is the difficulty level appropriate for the audience, or is the game overall too hard or too easy?
2. As the player progresses through the game, we expect the game to get harder to compensate for the player’s increasing skill level because they are getting better; does the difficulty increase at a good rate, or does it get too hard too fast (which leads to frustration), or does it get harder too slowly (leading to boredom while the player waits for the game to get challenging again)? 
3. If your avatar increases in power, whether that be from finding new game objects like better weapons or tools or other toys, gaining new special abilities, or just getting a raw boost in stats like Hit Points or Damage, are you gaining these at a good rate relative to the increase in enemy power? Or do you gain too much power too fast (making the rest of the game trivial after a certain point), or do you gain power too slowly (requiring a lot of mindless grinding to compensate, which artificially lengthens the game at the cost of forcing the player to re-play content that they’ve already mastered)? 

Why Progression Mechanics? 

Let's consider what is the purpose behind progression. What is it useful for?

Ending the game 

In most cases, the purpose of progression is to bring the game to an end. For shorter games especially, the idea is that progression makes sure the game ends in a reasonable time frame. So whether you’re making a game that’s meant to last 3 minutes (like an early-80s arcade game) or 30-60 minutes (like a family board game) or 3 to 6 hours (like a strategic wargame) or 30 to 300 hours (like a console RPG), the idea is that some games have a desired game length, and if you know what that length is, forced progression keeps it moving along to guarantee that the game will actually end within the desired time range.

Reward and training for the elder game

In a few specialized cases, the game has no end (MMOs, Sims, tabletop RPGs, or progression-based Facebook games), so progression is used as a reward structure and a training simulator in the early game rather than a way to end the game. This has an obvious problem which can be seen with just about all of these games: at some point, more progression just isn’t meaningful. The player has seen all the content in the game that they need to, they’ve reached the level cap, they’ve unlocked all of their special abilities in their skill tree, they’ve maxed their stats, or whatever. In just about all cases, when the player reaches this point, they have to find something else to do, and there is a sharp transition into what’s sometimes called the “elder game” where the objective changes from progression to something else. For players who are used to progression as a goal, since that’s what the game has been training them for, this transition can be jarring. The people who enjoy the early-game progression may not enjoy the elder game activities as much since they’re so different (and likewise, some people who would love the elder game never reach it because they don’t have the patience to go through the progression treadmill).

What happens in the elder game?
 
In Sim games and FarmVille, the elder game is artistic expression: making your farm pretty or interesting for your friends to look at, or setting up custom stories or skits with your sims. In MMOs, the elder game is high-level raids that require careful coordination between a large group, or PvP areas where you’re fighting against other human players one-on-one or in teams, or exploring social aspects of the game like taking on a coordination or leadership role within a Guild.

In tabletop RPGs, the elder game is usually finding an elegant way to retire your characters and end the story in a way that’s sufficiently satisfying, which is interesting because in these games the “elder game” is actually a quest to end the game!

What happens with games that end?

In games where progression does end the game, there is also a problem: generally, if you’re gaining power throughout the game and this serves as a reward to the player, the game ends right when you’re reaching the peak of your power. This means you don’t really get to enjoy being on top of the world for very long. If you’re losing power throughout the game, which can happen in games like Chess, then at the end you just feel like you’ve been ground into the dirt for the entire experience, which isn’t much better.

Peter Molyneux has pointed out this flaw when talking about Fable 3, where he insists you’ll reach the peak of your power early on, succeed in ruling the world, and then have to spend the rest of the game making good on the promises you made to get there… which is a great tagline, but really all he’s saying is that he’s taking the standard Console RPG progression model, shortening it, and adding an elder game, which means that Fable 3 will either live or die on its ability to deliver a solid elder-game experience that still appeals to the same kinds of players who enjoyed reaching that point in the first place.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.

March 2013: Pacing

Hello!  I was at a local IGDA meeting when the speaker remarked that great games are not always original ideas, but that the game designers had all the elements, right pacing, and balance to create a great game.  In fact, we have a long honored tradition of building on top of other games, in particular board games and other social games.

I remember loving a casual game called Fairies.  Yes, it was the same gameplay mechanic as Chuzzle. There was just something about the theme, the story, music, and pacing of Fairies that really appealed to me.  While I knew about Chuzzle, the whole fuzzy balls and chemistry beakers never appealed to me and I felt that the difficulty ramped up unevenly.  I have played other classic puzzle games like Puzzle Bobble and have experienced uneven levels.

In bigger games, one might think about pacing as lulls and highs, or variety in gameplay.

• How would you define pacing in videogames?
• How does pacing affect the player experience?
• How do you control pacing in videogames?
• What would you consider to be great pacing?
• What games are good examples of great pacing?