A version of this article first appeared in the May 2010 issue of Game Developer magazine.

In 2004, the Red Sox were down 4-3 in game 4 of the American League Championship Series in the bottom of the ninth inning.  Their hated rivals, the Yankees, had won the previous 3 games and were 3 outs away from going to the World Series.  But in one of the most thrilling championship series of all of sports, the Red Sox managed to tie the game in the ninth inning, win the game in the 12^th, and proceed to win the ALCS and then the World Series.  Seriously, what are the odds?

Thanks to a bunch of fans, we know exactly what the odds are.  Baseball as a sport lends itself to statistical analysis – a hobby advocates call Sabermetrics.  Unlike other team sports, baseball has a relatively low number of variables – it really comes down to the duel between the pitcher and batter – so it’s easy to quantify the value of any given player in any given situation.  There are few parts of the game that have not undergone statistical analysis.

So when we ask, “what are the odds the Red Sox would win game 4?”, we know exactly: in the history of all baseball games that have ever been played, a team that has been down one run with no outs at the bottom of the ninth inning has won 23% of the time.  When Kevin Millar got his walk, that percentage jumped up to 37%.  One stolen base later — making the situation a runner on second with no outs – and  the odds shot up to 47%.  When Bill Mueller knocked him home to tie it, the odds shot up to 73%.

There are two takeaways for the aspiring game designer.  The first is that the odds of victory (what Sabermetricians call ‘win expectancy’) can absolutely be quantified.  There are, in fact, iPhone apps that you can take with you so you can find your team’s win expectancy at the ballpark.  The second, more important takeaway is that that the low win expectancy of the Red Sox, that 23% number, is what made the game great – a game that, out of hundreds of championship baseball games that have ever been played, is still discussed today. It is, quantifiably, the underdog triumphing over long odds.

A graph of the win expectancy of Game 4 Red Sox-Yankees 2004 ALCS over time.  Note the spike when Bill Mueller singles in the run in the 9^th inning.

Games and Win Expectancy

Movies play with win expectancy all the time.  When Darth Vader is trailing Luke in the trench near the end of Star Wars and breathes “I have you now”, you feel like Luke’s chances are hopeless (perhaps sabermetric geeks would say sub-10%).  But then Han comes in like a cowboy and clears Luke for the shot.  Han’s appearance is epic, but it is the emotional low beforehand that makes his appearance so fist-pumping.

Overcoming great odds is just one of the scenarios that can provide a unique emotional high to the player, and that can make a gaming experience even more memorable and compelling.  However, game designers have some real problems when attempting to manipulate win expectancy.  The first is the role that player skill plays into the equation: a 90% win expectancy for a seasoned Ninja Gaiden player may be only be 10% for the casual.

The more pernicious problem is that underdogs lose most of the time.  Game 4 is unusual because the Red Sox, statistically, should have lost.  But if a boss fight has an actual win expectancy of 10%, this suggests that the player should flat-out fail 9 attempts out of 10.  In practice, most players will throw their controllers through their flatscreens in frustration.  Still, those who have finished a boss fight with a sliver of health left know that the emotional peak that results is often worth the frustration that led us there.

On top of all of this, a win expectancy that is too high may indicate a game that is ultimately not very interesting.  A game where victory is effortless is one where the player fails to get emotionally invested and, as such, it’s very easy for him to put the controller down.

The Illusion of the Underdog

So we want players to feel like they are riding on the edge of failure, without actually putting them there.  This isn’t insurmountable  – the movies do it all the time.  Cognitively, you know that Luke is going to blow up the death star, but in the midst of the roller coaster ride, you’re fooled.

One easy way is to conjure the illusion of toughness – most commonly this is done with puffery.  Scaling up the boss in size, giving him an intro speech, giving him extremely showy particle attacks, or even doubling the size of his health bar can all instantly create the sense that you’re expected to fail.  Another is to simulate attrition, even fake attrition.  Star Wars does this by winnowing down Luke’s wingmen one by one.  In games, this can be done by knocking off a player’s armor, breaking his weapon, or killing a companion.

Most games, like the God of War series, set up boss fights with a good amount of trash that can easily be overcome.  Just as a low win expectancy can make the resulting victory that much higher, having an easy baseline experience can make a boss feel much tougher than he actually is.

Playing with the player’s health bar is another way to create an illusion that the player is closer to death than he actually is.  In Diablo, a boss creature can knock a player’s health way down – players can easily resolve this by quaffing a potion, but seeing that health bar go that empty so quickly dramatically adjusts his perceived win expectancy downward, while still giving him good statistical odds to recover if he plays correctly.  The health bar can also unlock functionality: tanking Paladins in WoW get access to a talent that results in them taking less damage when they are below 35% health (which helps put them in that ‘danger zone’ more often), and some fighting games give players access to super attacks that are only available if they are below a certain health threshold.

Player vs. Player Activity

Most single-player games are designed, nowadays, to let the player win – they might have an overall win expectancy for most of their content at about 95%.  However, this is not the case in player vs. player scenarios.  In a one on one StarCraft match, for example, a player’s chances of winning start at 50% – and that assumes the players are evenly skilled.  Add contestants, such as in a Quake Deathmatch or a large game of Risk, and the individual’s chances drop with each additional contestant.  This is especially problematic in games where both kinds of content exists – a PvE player in an MMO like World of Warcraft or Warhammer Online who is used to winning 95% of the time may have trouble adjusting to the sudden increase on failure on their part.

This is one of the reasons that team gameplay is important – having only two teams in Capture the Flag means a Quake player is much more likely to experience victory than in a Deathmatch.  Furthermore, to some degree, it disguises a player’s own contribution to failure.  If you lose a one-on-one match, you have no one else to blame.  If you lose a four-on-four match, that sense of failure is ameliorated.  And sometimes, a low-skill player will experience victory by osmosis.

Calculating win expectancy in situations with asymmetric power can be extremely complex.  In the board game Illuminati, the Gnomes of Zurich are by far the most powerful Illuminati faction, but according to Steve Jackson, they don’t win disproportionately often.  It turns out, most other players recognize that power, and gang up on the hapless sap playing the gnomes.

The Illusion of Closeness

The polling for the presidential election of 2004 was never even close – nearly every poll in the election gave George Bush leads over John Kerry .  This was even more true in 2008 – other than a short spike around the Republican convention, Barack Obama had convincing leads over his opponent John McCain from the moment that he secured the nomination.  In both cases, the frontrunner played defense, avoided making any mistakes, and secured the election with relatively little doubt.

You wouldn’t know that from the election coverage.  Every news story made it clear the underdog was within arm’s reach of the frontrunner, and that the election was anyone’s game.  Close elections sell more newspapers than blowouts.  The candidates were complicit, too.  The frontrunners wanted the election to feel close to create pressure on their base to turn out.  The underdogs have to seem to have a fighting chance if they want to attract donations and volunteers.

Close matches are compelling because the expectations around a contest remain in doubt.  In blowouts, there is precious little doubt, and the contest ceases to be interesting.  Ensuring that there is doubt, that there is always an angle for an underdog to get back into the thick of things, is a time-honored design principle.  Consider Mario Kart: there are a lot of powerups in the game that allow you to attack other racers on the track, but by and large most of them fire forward.  One well-aimed tortoise shell can knock a frontrunner to the back of the pack.

Having slightly opaque game mechanics can also create this doubt.  In Settlers of Catan, the player may purchase cards that offer secret victory points.  The leader may have a convincing lead over other players, but anyone who has cards in his hand may actually be able to surprise the leader and steal victory, which maintains interest in the game.

The Future of Win Expectancy

Game designers are already becoming more and more sophisticated about building a good win expectancy cadence in their experience – ensuring that players alternate between assured victories and more challenging content.  I expect we will see more sophistication of this nature in the future.

Already, games are starting to notice that players are failing more often than expected, and asking them if they want to adjust their game’s difficulty on the fly.  In the future, more will start doing this behind the scenes – to have AIs determine the worthiness of their foe, and adjust automatically.  This is already commonplace in racing games like Kart Rider, although designing systems to do so without cheapening the accomplishments of your more hardcore players takes more design thought than you might expect.  Left 4 Dead similarly uses an ‘AI Director’ in order to provide an appropriate level of challenge to whichever four players have found their way into a match.

Game mechanics like Xbox Achievements and Boasts in Fable are already helping players to make this choice manually.  More casual players can just play the game as presented, and experience a default win expectancy that was balanced for them.  Hardcore players who can blow by that challenge as-is can choose to make the fight harder: in Fable, players can boast they can defeat a boss unarmored, or without taking damage.  In World of Warcraft, players can earn achievements for killing bosses without losing any raid members, within a time limit, or in other ways that provides hardcore players a challenge without bending the difficulty curve to a place where more casual players can never conquer it.

Surprising players is important – they need to expect the unexpected.  But it is equally important for game designers to cater to what players do expect.  Doing so will give the players greater understanding of their own failure, and increase their satisfaction when they succeed.  Win expectancy is a powerful tool – designers should be willing to cheat and manipulate it in order to provide the appropriate sense of challenge and tension in their game experiences.

This article first appeared in the January 2010 issue of Game Developer magazine.  It has since been reprinted on Gamasutra at this link.

How Realistic is Too Realistic?

One can ask the makers of The Polar Express, the animated Christmas film released just in time for Thanksgiving in 2004. Despite huge investments, a big-named director, and Tom Hanks providing the voice and mocap animation for several roles, the film struggled at the box office, getting swamped by another animated film, The Incredibles, released five days prior. Around this time, the concept of the Uncanny Valley entered the public mind.

The Uncanny Valley is a theory that most game artists (especially modelers and animators) are well aware of now, but it wasn’t always the case. Around the same time The Incredibles was trouncing Polar Express in the box office, too many art directors believed real games made for gamers had to chase photorealism in order to be successful. World of Warcraft eschewed all of that for a cartoony appearance, and in doing so blew past all the competition and expectations. Three years later, Team Fortress 2 would do the same for a shooter market that had previously obsessed over realism to an insane degree.

Realism is a choice, both for artists and for designers — but it can also be also a trap, and one that is perilously easy to fall into. In art, chasing realism is expensive — technology can provide incredibly lifelike visuals now, but it’s also increasingly expensive and time-consuming to generate that content, and the end result is a screenshot that looks not all that different from competitors who are also chasing realism as an end goal. But realism isn’t just a pitfall for artists — game designers also flirt with realism as a source of inspiration for their game mechanics, often with staggering implications to their game designs.

The Realism Trap

The unwary designer can get into trouble by trying to follow realism too closely. Making a scene look realistic doesn’t necessarily make it look more beautiful, fantastic, or intriguing. Similarly for designers, a game mechanic that is realistic doesn’t necessarily make the game fun.

A common way that this makes itself evident inside our game designs is the rise of sandbox games. Once a mechanic largely limited to strict simulations, the success of Grand Theft Auto has resulted in game designers trying to shoehorn sandbox design principles on almost every genre of gaming. In sandboxes, players are free to go anywhere and tackle content in almost any order, rather than be drawn along a linear game path with unreachable areas blocked off by unrealistic obstacles or invisible walls. True, it’s more realistic, but it’s also more expensive to build and test that world.

And even if it weren’t, sandbox gameplay may fight with other tenets of the design. For example, most players get confused and overwhelmed when told to find their own fun, and systems need to be devised to lead them to interesting activities. Compelling narratives are harder to tell, because designers lose control of the order and flow. Sometimes issues are more insidious: Burnout: Paradise‘s open world structure made it difficult for players to attempt to do the same race or challenge twice in a row, as many racing game players want.

Are sandboxes inherently bad? No — some of the finest games in the world are sandboxes. But injecting this level of realism into a game has very direct repercussions on the cost and design of the game that the designers must be mindful of.

When Realism Creates Unrealistic Behavior

In the early days of Everquest, it was not uncommon to stumble upon another player in the wild who was throwing himself off a short cliff over and over again while spewing gibberish indecipherable to passers-by. Use-based advancement was to blame: While most of Everquest‘s advancement model was centered around a classic level-based advancement system, the non-combat skills like “Language” and “Safe Fall” advanced as the character performed in-game actions. Thus, our mysterious cliff diving tonguespeaker was someone whose character was, ostensibly, learning new trades.

The ironic thing, of course, is that these use-based systems are designed to be realistic — practice making perfect, and all. Some players and designers are bothered by the idea that you can learn how to speak Orcish by killing kobolds until you gain a level. A learning-by-doing system makes perfect sense to them.

But in practice, learning-by-doing falls into sort of an uncanny design of game mechanics. Efficient advancement in a use-based system often nudges people to perform odd gameplay that is frequently repetitive as well as not particularly fun. Rather than feeling natural and elegant, the game mechanic feels unnatural and contrived, and worse, draws attention to itself in the process. Learning Orcish by killing kobolds may not be terribly realistic, but at least at no point is the player being asked to do something he didn’t want to do anyway.

Realism vs. Consistency

There’s a lot to like about Gotham Central. The DC comic was a police procedural set in Gotham city, and tried to describe what it was like to be a detective and have to clean up after Batman and Joker slugging it out amongst the rooftops. The comic ran for 40 issues, earning meager sales but strong critical praise. Those who loved it often cited the series’ gritty realism. Which is interesting, given the series still hinges on a man who fights crime dressed as a bat.

A lot of times, people think they want realism when what they really crave is internal consistency within a given universe. Gotham Central feels a lot like what happens if you merge the classic Dark Knight with gritty TV cop fare like The Shield. The goal is to make the rest of Gotham as real as possible, and the end result is a world where Batman is still amazing and mysterious, without becoming silly or ludicrous. He feels possible — even though he’s not.

Immersion is the goal. The player should be drawn into your worlds and experiences. Realism is good when it supports immersion, and bad when it gets into the way. For example, most single roomed buildings in games are huge, often with 18 foot ceilings. It’s not realistic, but the player rarely notices. On the other hand, he always notices when, in a small room, the camera moves in too close to see or do anything.

Jumping is an interesting place where realism and gaming diverge. Most games that have jumping allow ludicrously high jumps — often a character can leap 6 feet high from a dead stop, because it feels right (see Inner Product November 2009). But recently, some action games — such as Gears of War — have been experimenting with not allowing jumping, since jumping around like a jackrabbit in heat isn’t particularly realistic. For the most part, these experiments have been successful — until the player finds an obstacle that he can’t jump but could in real life. Even worse, he could clear it by five feet in a game that allows jumping. The obstacle feels unrealistic, and worse, noticeably so. It’s a problem because it breaks immersion.

To some degree, the realism we are bound to is determined not by real life, but by our forerunners. Hit points linger as a concept because most games teach us that you usually hit what you swing at, but fights shouldn’t be over instantly. When an NPC tells you to “hurry,” he doesn’t mean it unless a timer appears on your screen. Rocket launchers aren’t just great weapons, they’re also solid ways to propel yourself up to a hard-to-reach ledge. But it’s not just games — most gun effects in shooters sound more like they do in the movies than they do in real life, because the theatre is where most players learn what automatic gunfire sounds like.

In all these cases, following unrealistic conventions can make the games feel better than taking a more realistic approach that breaks player expectations. Worse, breaking convention can make the game feel less realistic, even though it is more so.

The Place of Realism

Designers make concessions to realism all the time, of course. In the real world, it only takes one bullet from an assault rifle to kill a man. Building a breast plate from raw iron doesn’t happen in less than 10 seconds. If you get brought near death by the jet of a flamethrower, you aren’t likely to be hopping back into battle after a couple of first aid kits. This is before we get to the inherent fantasy of the worlds we build: worlds full of dragons, gangsters, or battle cruisers. And lest we cut out the mundane — short of The Sims, no games require your characters take bathroom breaks.

But realism can enrich a game as well. An MMO that has crafting can have a much more realistic economy than one that doesn’t, even if the mechanics of crafting aren’t realistic. An assassin that trades in poisons feels more real, even if game balance requires that poison be a minor damage over time effect instead of being immediately lethal. Bouts of Madden that end with scores like 30–27 feel more real, even if it takes five minute quarters to keep the scoring that low.

At the end of the day, players play games escape the real world, so designers shouldn’t be such a slave to it. Players are hoping to live a fantasy provided by the game designer. Good games make those fantasies as immersive as possible, but they don’t always do that by making them realistic. Sometimes, too much realism gets in the way.

A version of this article first appeared in the September 2009 issue of Game Developer magazine.

There are songs that are kind of catchy.  Others you just can’t get out of your head.  And once, ever so rarely, you hear a song so memorable, you could swear you had heard it before.  Song taste is highly personal – different people react to different songs in different ways – but the breakout hits are the ones that resonate on this level with a large number of potential fans.

Creating a breakout hit is no easy manner, in part because the songwriter’s instincts can often be wrong.  Steven Tyler of Aerosmith was reportedly surprised that “St. John” from Permanent Vacation was met by collective yawns of their concert-goers. He thought he knew what made a hit – the song had an interesting riff, topical lyrics, was meaty to play live – but somehow just didn’t reach the fans.  Today, the song is a footnote in the band’s music catalog.

All creative fields are like this.  Sometimes films and books just catch fire.  Sometimes, surehanded directors stumble.  Pop radio is full of songs like “the Macarena” and “I’m Too Sexy”, all done by bands that later proved to be one-hit wonders unable to repeat their success.  And it’s true of games as well.

Basic Resonance

Resonance – the idea that some art is simply more immediately arresting and intriguing than others – exists in games as it does in film and music.  But how much of a black art is it, really?  Is resonance something that can be willfully added, shaped and controlled?  Or is the concept that some games just stick better than others mostly something best left to luck and fate?

Most people reading this magazine are probably pretty comfortable with the idea that games are fun and sell well for good reasons having to do with good design, technique and craftsmanship.  The idea that part of game design is left to fate can be somewhat unnerving.  But this can be a trap – the idea that there is a formula to good art is seductive, but it also ignores the subjective nature of art.  Sometimes, a book, a movie, or a game, just feels good the first time the players get their hands on it.

In his book Blink, author Malcolm Gladwell cites several studies that points out most people decide whether they like or dislike something in seconds, if not nanoseconds.  Whether or not a song lingers often is decided by the opening bars.  Whether or not a film resonates can often be decided before the opening credits finish.   Whether or not you’re going home with the girl at the bar can often be decided before you blurt out your pickup line.

The First 15 Seconds

It’s no secret among game designers and executives that they have a very short period of time in order to earn a player’s trust and attention.  What may be underestimated is how short that time period is. Producers love to press on developers about the ‘first five minutes of gameplay’, when in actuality, a customer may only give the game designer 15 seconds.  The player may play beyond that, but by then his initial impressions are set and must be overcome.  If Gladwell is right, then it’s useful for the game developer to obsess over whether or not their first 15 seconds are resonating with test audiences.   Think that’s too short?  Consider: the viral hit Youtube of a Prairie Dog turning his head to the camera is :08 seconds long.

I once heard of a programmer who, in an interview asking what he was most proud of, said he crunched and worked overtime for a month in order to get jumping exactly perfect on his last game.  His interviewers were unimpressed by his answer, but I am.  What is a player more likely to do in his first 15 seconds but to run, and then jump?

Good, smooth movement is the cornerstone of many games, especially platform games.  Having smooth jumping increases the chance of resonance.  More importantly, bad jumping is incredibly dissonant – if players feel the movement controls in the first 15 seconds are clumsy or sluggish, they are likely to extend this prejudice to the game as a whole.  The designer then has to work harder to overcome these initial judgments.

A game designer’s job, then, can be thought of as trying to build resonance, and whenever possible, remove game aspects that are dissonant for the player.  There is undoubtedly elements that are impossible to predict or ascertain, but aspects are certainly within the control of the game developers and should not be left to pure chance.

Resonance of Familiarity

So what goes into resonance?  One cornerstone is a certain level of player comfort – feeling comfortable with the setting, the mechanics and his role, as quickly as possible. If getting into the game feels to the player like he is slipping into a comfortable pair of shoes, the game designer has probably successfully built resonance.  This is one reason why licenses are so attractive to game designers, but even those working with original designs can leverage this

Alpha Centauri was a solid and needed evolution to the gameplay found in its predecessor, Civilization II.  It offered more depth and strategy than previous Civ games, while still streamlining it in ways the classic Civ design needed streamlining.  And yet, when I played it, I mostly felt an urge to find my old Civ disks.

Alpha Centauri was more polished, more streamlined, prettier, and more atmospheric as a whole, but I just couldn’t get into the game the way I could into Civ.  I found it’s easier to get excited over discovering Writing, building catapults and crushing the Greek Empire than discovering Applied Gravitonics, building Super Tensile Solids and crushing the Human Hive. The former mean something to me and my life.  These ideas have resonance, and they grant that to the game.

A similar example in gaming can be found in Everquest vs. Asheron’s Call.  Everquest chose to populate their worlds with standard D&D fare – trolls, orcs, gnomes and dragons.  By contrast, Asheron’s Call went to great pains in order to create an entirely invented bestiary – no orcs and trolls here, instead players fought creatures with names like Mattekars, Lugians and Mosswarts.  AC may have won points for originality, but for Everquest players, most of whom were playing an online RPG for the first time, the familiar setting and enemies undoubtedly made the game feel like a sort of homecoming.

A Hint of New

But familiarity can (and often is) taken to a fault.  Right now, there are musicologists diligently working on algorithms to detect whether any given pop song will be a megahit – and trying to define algorithms to write the next hit song.  Some musicians are concerned about this – I’m not.  Could the result be anything other than ‘formulaic’?

The games industry is sequel-heavy – it is one of the few creative fields where sequels frequently out-earn the original – but at the same time, the market demands novelty.  Players want new way to interact with their old classics and games with little new to offer are viewed as glorified expansion packs.

At the same time, if the player loves a game or a genre, they don’t look kindly to adjustments to the classic game design they see as a step backwards.  Players, essentially, want new features that feel like they should have been there the whole time.  Studios that trade in sequels, such as EA’s Madden team, are acutely aware of this delicate balance, and take great pains to try to find the franchise’s logical extensions.  Sometimes, they stumble – the Quarterback Vision feature from Madden ‘06 was received by many fans as making their beloved game more difficult and wonky to play.  But sometimes, they score – when they announced the ability to manage your Madden team from the web this E3, the first words out of my mouth is ‘that’s so obvious!’  If you find yourself saying ‘that’s so obvious!’, it’s very likely you’ve found a new feature with resonance.

Changing Tides

Tastes are always changing as well.  What resonates today may not have that sort of impact in the future.  “Spirit in the Sky” was a monster hit in 1969, selling more than 2 million copies, and it was named one of the top 500 songs of all-time by Rolling Stone.  Would the song have nearly the impact if it had been released last year?  Doubtful.

Tastes change just as quickly in the game space as well –ask any adventure game fan.  What’s more, the skills of game players tend to graduate as well.  Competitors to Blizzard hoping to make the next great WoW-killer have a tricky balancing act to achieve.  On one hand, you want the gameplay to be familiar and inviting to the WoW population to maximize resonance.  On the other hand, though, WoW is now four years old, and even devoted fans are now eagerly looking ahead to the next logical evolution of the genre.

This has some unexpected side effects.  Modern FPS players who go back and play Castle Wolfenstein are often shocked at how far the genre has come – since then, the genre has added full 3D environments, multiplayer, jumping, crouching, rolling, cover, alternative fire modes, and full physics simulations.  What the designer has to be wary of is the opposite – that the player who has never played a first-person shooter now must learn all at once the skills other FPS players have learned over 20 years.  Any time a game has a steep learning curve, the barrier to resonance is all that much higher.

Dissecting Resonance

Still,  resonance has a large intangible component to it.  Personally, I find it intriguing to consider the one-hit wonders and unusual hits.  What was it about “Song 2” that Blur could never replicate? Why did Katamari Damacy catch on?  Even more intriguing is the internet meme.  Did ‘All Your Base’ really merit exploding into the public consciousness?  Lessons of resonance abound.

Building games that stick is a black art, but not unteachable.  Designers striving for resonance should learn to balance the familiar with the new, be obsessive about the first 15 seconds of gameplay, and do everything to remove dissonant gameplay elements, especially early in the game experience.  And don’t just trust your gut – developers are too close and familiar with the game to be objective about it.  Run playtests, as early and often as you can.

I remember a designer on Guitar Hero saying, shortly after the game shipped, the studio had no idea if the game would succeed or not.  The series has since sold more than 25 million units and Activision claims it to be the third largest franchise in video game history.  It’s easy to see why – the game just resonates.