Tag Archives: Metagames

Article, Game Design

Archive 4: Analysis of Diablo 2

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This article was written out of necessity back in 2005… I was looking for a new gig and one studio asked for, as part of its application, a paper analyzing one of several possible games. Diablo 2 was on the list. Great timing! I had gone from X-Men Legends, where I learned the ups and downs of action RPG’s to working on Lord of the Rings Online, where discussions of scope and the feasibility of various online choices was the topic of the day. Both games set a lot of speculation stewing in my head about what could be done with the Diablo formula and why it was successful in the first place.

Analysis of Diablo II

by Patrick Lipo

Introduction

When the first Diablo was being previewed in 1995, most people (myself included) were blissfully unaware of its all-out potential. “I played that exact same game on mainframes 10 years ago,” we’d say, patting ourselves on the back. While we were congratulating ourselves, we had forgotten how those games had something that kept us playing and playing.

Blizzard could have simply created a polished copy of Rogue, Moria or Hack and done well, but they managed to refine the experience even further. Diablo was about giving gamers what the wanted, or perhaps what they needed, whether they knew it or not. Building off that success, Diablo II was able to add significant new features without spoiling what the original did right.

What Was Done Well

Simple World Presentation

2D may be “dead” to some, but the use of a 2D field was key to Diablo’s initial accessibility to millions. Everything the player needed to know about his surroundings was right in front of him. North was always up, just like a map. Yet, the isometric view and the 3D-rendered sprites kept the game from looking old. The Sims made a similar choice, and enjoyed similar ease-of-use.

Simple Controls

Click where you want to go. Click what you want to attack. What could be simpler? What Diablo I & II offers is a intuitive, rhythmic, and even mindless player experience at the lowest level. This allows the game to transcend the moment-to-moment battles and make people think about longer-term goals, such as completing the dungeon or gaining the next level. They could have added more moves to the player character (as Blade & Sword attempted), but would have clouded what worked so well, and pushed the emphasis to abilities and loot.

Frequent Rewards

From the very first Quill Rat slain, the coins spew forth, highlighting the strong cycle of rewards in Diablo II. While combat with a single opponent is simplistic, each enemy carries its own surprise contents. Who cares if a tiny Fetish unrealistically explodes like a piñata filled with gold, weapons and armor? Each and every kill feels different and rewarding because the player gets the pleasure of collecting new spoils, and rooting through a full inventory of randomly-generated items can be like a miniature Christmas morning.

The level progression curve is equally rewarding. While an MMO or pen-and-paper derived RPG such as Baldur’s Gate must space level advances with huge sessions of play, Diablo II manages to reward the player often, beginning at about five minutes and smoothly progressing towards around an hour. These frequent level-ups give the player yet another gift-unwrapping session of choosing which skills to acquire or advance. And while another game might provide finely-granular skill points to allocate, each Diablo II skill improvement is noticeable, with a beefy jump in damage, number of minions, or power duration.

Identifiable, Overlapping Goals

A major force in Diablo I and II’s long-lasting appeal is their presentation of goals. The player’s quest objectives are bold and easy to understand, such as “go here”, “find this” or “kill all of X in this area”. Beyond quests, the player can easily identify personal goals for his character, such as “level up”, “get this high-level spell”, or “become powerful enough to wield this weapon”. All these objectives are dangled in front of the player like carrots on a stick… You go into a highly-populated dungeon and you know what to do. You look at your skill tree and you see what prerequisites you need to summon an Iron Golem. Check your inventory and you see that sword that you just need three more points of strength to wield.

Coupled perfectly with this is the way that all of these goals overlap. In some games, the completion of a level gives the player an opportunity to catch their breath and consider quitting their session. In the Diablo series, the completion of a dungeon may bring you most of the way to earning another level, encouraging you to finish it off. However, once you earn that level, you might be halfway through another dungeon, drawing you to player just a bit longer to finish that up… And so it continues.

My first awareness of this dynamic came from playing the original Civilization, which had a similar loop of drawing the player from completing one more unit to finishing up that last attack before quitting for the night. Encouraging this sort of compulsive play behavior is not desirable in every type of game… Tetris’s strength comes from the ease of picking it up for a quick game, and massively-multiplayer games become more expensive to host if their players are active for 16 hours a day. However, for games such as Diablo II and Civilization, the goal structure had the effect of keeping people playing until the light of dawn began streaming through the window…

Randomness and Repeatability

The random generation of items and dungeons in Diablo II is something that outwardly sounds like a nice bullet-point for the sales flyer, but ultimately is integral to the series’ enduring presence. The dungeons have enough variation to make successive plays through (with the same advanced character or an entirely new class) different enough to keep the sense of discovery, but they are not so random as to make the dungeons appear “patchwork” (as seen in the PSP release of Untold Legends). The monsters have a sliding-scale difficulty that helps them remain challenging throughout your replay curve. The items have a fantastic, smart variability that provides statistics and powers that are interesting at the times you really want them. That last feature is something that Dungeon Siege had difficulty replicating (where you often saw Colossal Two-handed Mallets of Wisdom™ or Magic Wands of Excessive Strength™).

Integration of the Meta Experience

The effort that was put into making Diablo II replayable was exploited to the fullest in providing a metagame as well. Once the player completes the full story, it wraps almost seamlessly into the next play-through at a higher challenge level. The advancement curve is such that multiple completions are needed to fully experience everything a class has to offer (and even then there are other classes to explore). This embrace of the player’s experience above and beyond a single telling of the game narrative is something that more games should incorporate.

Minimizing Dead Playtime

One final element that helped give the Diablo series appeal was its conscientious reduction of dead time at any cost. Most RPG’s have some measure of uneventful busywork or travel, but elements such as the Town Portals virtually eliminate any dead travel time in the game. RPG purists doubtless were infuriated at this break with “reality” and “world sense”, but this addition had a far, far, far more positive effect on the player experience than a negative one. Diablo II added sprinting and item highlighting that identified and alleviated tedious bits that existed in the first game, showing that the developers considered this issue important to track down and solve.

What Could Be Improved

More Random Side-Quests

The randomized content of Diablo II is inspiring, as is the simplicity of their quests. One thing that I would do to maximize the value of such a powerful and versatile system is create far more simple side-quests than the game originally provided. The content structure and world layout of Diablo II makes a natural potential for creating hundreds of quests with variable properties that an industrious (and thorough) character can embark on. The component-based map structure allows the game to sprinkle quests into almost any map, each with a named monster and a rare or unique drop, so that adding new dungeons to a previously featureless play zone can provide an entirely new feel. There could be only a limited number of quests available for each play-through, so that it might take the player dozens of characters to see all of the possibilities.

These side-quests could also work with Diablo II’s replayability. By tracking the player’s completion history with different characters, the game could open up specialized quests on subsequent run-throughs. Complete the paladin on the hardest difficulty and your next character might get some holy artifact. This could bring more long-term goals than Easter eggs like the cow quest already provide.

Feedback for Hit-or-Miss

A difficult issue with real-time games that use to-hit rolls is what to do when the character misses his attack. Typically, a miss is shown as a normal hit with no effect or sound. Diablo is this way, allowing the player to click frantically at an enemy, but with only some percentage of the attacks resulting in damage, the rest passing through uneventfully. The player feedback on this is weak, resulting in a little bit of mystery around what is a “good” or “bad” attack total.

Having taken on this issue in the action-RPG X-Men Legends, there are a few things that can be done to help better represent it to the player. The first is to play a “dodge” or “parry” animation on the opponent that shows that player why damage was not done. This can be exciting, adding in new motion to the interaction, but it must be done carefully to avoid confusing the player (for example, big dodging motions might make the player think that the AI is doing something to keep away from him, as though he is doing something wrong). It can also put new pressures on the character animators, particularly if you wish to synchronize the animation with the incoming attack (although this is less necessary with Diablo’s smaller characters). Finally, in a game with many attacks coming into a single target, deciding which ones to respond to can become almost arbitrary.

In X-Men the above was impractical due to memory and manpower limitations, so an alternate approach was taken. A failed attack roll is deemed a “weak hit”, with almost no effect and an unsatisfying “thup” sound. For successful hits, an effect is selected from a set of increasingly intense impacts, depending on how much the player’s attack totals exceed the enemy’s defense. In addition to the hit sound, a secondary “rumble” sound is mixed in to give extra “oomph” to powerful hits. The result of this tactic is that when the player first meets a new creature that is fairly tough, he does weak hits, but as he begins to gain experience and outclass it, he is rewarded by much more powerful effects to go with his increased damage-dealing.

More Dungeon Interactivity

Diablo dungeons are very good at providing exactly what they need as far as functionality. Their interactivity needs are very simple… a key may unlock a door or trigger an animation, flipping a bit in the dungeon and little else. This makes “what you do” in the dungeons fairly limited. By adding a few moving elements such as sliding walls and mobile platforms, certain situations could gain more of a time element, such as protecting a caravan or moving through an area before a wall crushes the player.

Also, if destructible structures and walls were added, player spells could have much more tangible impact on the world, and monsters would be able to smash their way through obstructions for dramatic effect.

Encounter Generation

At this point I’ve given suggestions on content, presentation and technology, but played it fairly safe (any schlep can say “more quests!” or “break stuff!”), so I’ll add something that might have more impact on Diablo II’s gameplay. The standard play structure of Diablo II involves creatures that sit and wait for you to clear them out, after which an area is empty until reset. For the sake of contrast, this could be enhanced by creating encounters that come to the player instead. These could be used to occasionally liven up travel through a cleared-out area, or add tension to certain objectives with ambushes, retaliations or pursuits.

These encounters would need to be generated with the same care as the rest of Diablo II’s randomized content, fitting with the appropriate biome, challenge level and terrain features. They would also have to be provided at carefully timed moments, so as to not betray the feeling of accomplishment that a player feels when walking through an area he devastated. A useful technique would be to let the player in on exactly what is happening by announcing the attack with a battle cry or even a special title (“Raptor Vengeance!”) when one is triggered.

In the case of random quests, these encounters could greatly enhance the sorts of events that can occur. Finally, generated encounters could potentially provide the game with the feel of hand-crafted content without the manpower and testing challenges typically experienced by heavily scripted games.

Conclusion

I hope that this analysis of Diablo II was not so drawn out that I lost you two pages ago. The game at its core is so simple, yet it did so many things right. It is amazing that more games haven’t benefited from the lessons it brought to the industry.

Article, Review

Archive 3: Hail to the Prince

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This was the second article I wrote for Joystick101 in Spring 2004… Sadly enough, around that time, the site was pretty much dying on the vine. It tended to be down a lot. Since blogs and blog sites weren’t really too common yet, this was the only outlet for this content, so my participation in that forum pretty much died with the site. Again, when it was resurrected in 2007 it was relaunched with a WordPress backbone and the old content and community was reset.

Play Appraisal: Observations of a Developer
By Patrick Lipo
March 2004

Hail to the Prince:

When I heard about the development of the most recent sequel to Prince of Persia (PoP: The Sands of Time), I along with many others indulged in skepticism. I loved the original and really enjoyed the second one, and look back at them as the absolute best in action-exploration. I do recognize some of this feeling as nostalgia, however, since they were also excellent examples of gameplay that was common 15 years ago… a 2D world filled with death-defying jumps and quick, easy deaths. Having tried the third title in the series, PoP 3D, it was easy to think of that game’s limitations as evidence that the series could not be updated to a modern 3D presentation without losing its spirit. That third title unfortunately had a very difficult time with establishing a working control scheme and camera, but in addition it focused on giving the player more choices and weapons for fighting (as a gamer might expect in one of today’s games), rather than considering PoP’s pedigree as a game of exploration.

When considering the difficulties that PoP 3D had, I cannot help but appreciate the core elements of the original’s design, and how bringing them to today’s game-playing audience would be quite difficult. For those that have not played the original Prince of Persia, it was a side-view exploration game, where your character progressed through various screens and overcame a variety of death traps in order to continue. It was a fairly brutal game, with sparse checkpoints and unforgiving traps that had to be overcome, including long falls, spring-loaded spikes, slashing blades, collapsing floors, and other instruments of serious peril. While the player did have a health bar to absorb damage from short falls and the occasional swordfight, running afoul of a trap generally meant instant, gory death.

Rube Goldberg:

While it is easy to categorize the Prince of Persia games as exploration mixed with sword-fighting and jumping challenges, after a period of time playing, you find an unexpected game buried within. For example, while some platformers rely on split-second timing and twitch abilities to accomplish their most advanced moves, each of the Prince’s leaps, crawls and dashes are fairly easy to accomplish. In fact, the famous wall-run created for PoP: Sands of Time is so forgiving that it almost feels as though the hero is guided along a track. It and most other of PoP’s moves (most notably in Sands of Time) are actually difficult to do incorrectly assuming you chose the correct time to use that move. Some hardcore gamers bash Sands of Time for that reason, stating that the game strays too close to playing itself rather than providing the player with sufficient challenge. To dismiss the game for that purpose is to miss an important aspect: Once the player has a general understanding of the moves and the obstacles that each move is capable of overcoming, the game becomes as much of a relationship with the classic game The Incredible Machine as Super Mario 64.

In The Incredible Machine, the player is given a set of pieces that each exhibit a certain behavior and accomplish a task by applying them to the level’s game board. In Prince of Persia, the player is trained to use a library of moves that can be used as tools to bypass obstacles, after which he is challenged to accomplish a task (typically reaching the exit) by applying them to the presented environment. In addition, the presentation of Prince of Persia has two other elements that are required to allow the player to approach an area as an intellectual challenge rather than a test of reflexes. The first element is that the player has a clear set of predictable properties that he can draw from. This is his “toolkit,” as it were, that he can draw upon to complete a given level (while Sands of Time was admirably seamless, each area was definitely presented as a stage or level to overcome). The Incredible Machine had easy-to-understand physical devices such as treadmills and rolling balls, whereas PoP draws from a set of very predictable moves. The “forgiving” nature of the wall-run that puts off the hardcore player suddenly becomes an asset because the player can look at a wall and immediately know whether he can clear that space with the move. The challenge, then, was not in executing the wall-run flawlessly, but rather figuring out when to use it.

The second element that makes Prince of Persia playable as a puzzle game is its ability to present the player with a clear view of the level for planning purposes. The original 2D versions could easily present “the game board” in this respect, as the viewpoint revealed all elements to the player. Nothing was hidden completely… even the collapsing floors in the original PoP could easily be revealed with a quick jump in-place. This gives the player the ability to plan and mentally execute the solution before committing his hero to it. In taking this formula to 3D, Sands of Time provided very grand, open-aired spaces for the hero to navigate. This had a fabulous impact in presentation, giving the feeling of very large spaces, and locations so high that a real sense of vertigo can be experienced. In addition however, it also provided a clear view of the elements that would be navigated, going so far as to provide a specially-placed camera that the player could always switch to in order to see the challenges ahead of him. Since the player was able to plot his route, if he were to die, it was always clear that it was due to some flaw in deduction rather than an arbitrary timing mistake or unfair “gotcha”.

A Ticking Clock:

Binding this puzzle-oriented gameplay together in the original Prince of Persia was an unusual method of limiting the player’s deaths. Instead of a set number of lives, the player is given exactly one hour to complete the entire game. Being killed simply meant some time lost from retracing one’s steps from the last checkpoint. This gives the game some urgency but also presents a tangible but relatively small penalty for taking risks. This penalty, however, grows naturally as the player progresses towards the end, since the amount of remaining time is constantly dwindling. The player will of course run out the clock many times over before he can even come close to the end of the game, but with each attempt he will improve his speed, and reap a quantifiable reward from increased prowess (additional seconds on the clock when starting each level). And naturally, as less time is spent in the early levels, the comfort zone where the player feels at ease with experimentation migrates into later areas of the game.

In addition, time in the game becomes a resource that the player wields with complete control. The player comes to understand that each time he fails the overall mission (runs out of time) it was due to his own actions and his general performance while playing the game. Conversely, as he improves, he saves time and gains security. Of course, once the game has been completed (within the allotted hour), the next challenge for the player is to complete the game in as short a period as possible. Since the hero starts out with very few health points and can only gain more by finding hidden potions, the best way to do get a low time score is to ignore the health-increasing potions and attempt to complete the game without the benefit of the extra health. The increased health mainly serves to give the player an advantage while swordfighting, so by leaving his health low, he must also put his faith in his fighting capabilities as well.

These aspects of Prince of Persia provide an intriguing meta-challenge to the player’s experience. Not only does he compete with the traps within the game, but he must look at a game session as a whole and determine how each early decision will affect the clock situation later on. He must also make decisions as to how much assistance he needs to complete the game without dying, rather than to take every gift offered him. The high-level “game” that continues in the player’s mind through multiple sessions of play is a puzzle all its own.

Let’s Do The Time Warp Again:

The choice to put a ticking clock in the original PoP added an excellent high-level playing experience, but when thinking about how it would be updated for the modern console audience, one must consider how it was built on an old-school approach to game challenges. The hero is quite vulnerable, and the player must endure multiple abrupt deaths as well as play through areas repeatedly after having to continue from a checkpoint. This sort of repetition and the inability to save games was familiar to gamers of the eighties and early nineties, but I am skeptical that this sort of approach would be accepted by the more casual gamers of today. However, to “fix” Prince of Persia by implementing infinite saves and higher character survivability could easily have destroyed the game completely. The very nature of death-defying jumps requires instilling fear and the risk of some sort of penalty. If there is no significant downside to poor performance, the player could become encouraged to blindly stumble through the challenges rather than to take a moment and plan his approach. Bringing in the timer from the original would have had its own raft of problems as well… The requirement of starting over from the beginning of the game repeatedly to make progress would probably have been seen as an extremely outdated mechanic and could have quickly driven away players. And to be fair (since I don’t consider modern players to be less worthy in any way), being stripped of one’s achievements again and again can truly feel frustratingly harsh.

In updating the series, The Sands of Time removed the meta-challenge of the time limit and relied on the more traditional approach of checkpoints and save games. This act brought the PoP series into a progression framework that fits modern players’ expectations, which was probably a wise choice. However, it still needed to address the issue of character mortality, which I would contend was necessary for the game to function as a puzzle game. With such deadly traps, the game could easily have become incredibly frustrating to play. Loading one’s savegame again and again would have been necessary to complete a difficult challenge (or to experiment with possible solutions to a level’s “puzzle”). The designers of Sands of Time, knowingly or unknowingly, were in a very difficult position. Either the game could retain its purity and risk being considered too hardcore, or it could have become too forgiving and transformed from a puzzle game to an action game. It is at this point that its predecessor, PoP 3D, most likely faltered.

The choice that was made for PoP: The Sands of Time to address this was an amazingly innovative one. In the final game, a limited resource of sand gives the player the power to rewind time at any moment, allowing him to retry any misstep. Essentially, it takes the player’s act of loading a savegame (which can be considered a “feature” that allows a player to retry any section of the game) and folds it into the game mechanics itself, going so far as to dedicate a controller button to that function. In most other games, when a player is forced to load a savegame repeatedly, the overall experience is diminished. In Sands of Time, the sand is a resource that is acquired through continuous adventuring, so the game becomes richer when players are forced to use it to retry a challenge. The interesting result of this strategy is that since the player is rarely forced to return to a save point, the game can present extremely difficult challenges while avoiding the seemingly inevitable frustration. Even more intriguing, the mechanic allows the player to almost continually experience new things and overcome new challenges, rather than retracing the same steps taken many times before. This choice may have taken a decidedly hardcore game type, an old-school platform-jumping title and restored its viability.

Crossing Swords:

While the Prince of Persia series has always had swordfighting, it would be foolish to think of fighting as the primary element (excluding PoP 3D, which focused a great deal on combat). In the original Prince of Persia, the guards blocking the hero’s way often acted as yet another puzzle piece… There were times when an opponent had to be dispatched in a certain way because he was located so he could kill the hero outright before he could draw his sword. However, in The Sands of Time, the fighting is more or less a pure interlude. This provides spikes in the game’s pacing but also simply sells it as a cinematic Arabian adventure. Luckily in SoT, the fights contained a few simple behaviors that provided a reasonably different experience than a typical brawling game.

The enemies in PoP: The Sands of Time are essentially undead, which means that they will always rise after each knockdown, until the player can reach a downed opponent and strike the killing blow with his dagger (which takes a short amount of time). The challenge of the combat then becomes buying time with repeated knockdowns, and trying to separate a specific enemy from the pack so that he can be dispatched without the player being interrupted by other enemies. The tactics then rely on the hero being very mobile, keeping away from the pack of enemies until he is able to dart in and strike at an individual. This mobility-centric behavior builds on the game’s technical strengths beautifully, since the game is very impressive when the hero is moving about, completing dodges, flips and rolls.

Conclusions:

  • The traps in Prince of Persia each have moves that can overcome them easily, but the real challenge is to deduce the series of moves that it will take to accomplish an entire area, akin to a puzzle game.
  • The overarching timer in the original Prince of Persia provided urgency, yet allowed the player to experiment heavily in the early game without significant penalty.
  • Allowing the player to get an even higher score (e.g. a lower time) by avoiding powerups allowed the player to choose their own risk and confidence level.
  • The time-rewind feature of Prince of Persia: The Sands of Time allows a very unforgiving set of traps to be viable in design.
  • Time-rewind more importantly means that the player can always be working on something new, rather than retracing steps time and time again.
  • The predictability and forgiving feel of the special moves serve a purpose of allowing the player to focus on deducing the moves rather than executing them.
  • The combat in Prince of Persia is simple, but in Sands of Time, the simple addition of a killing move allowed the fighting to become more about motion and looking cool than a single fight.

Playing through Prince of Persia: The Sands of Time recently taught me a fair amount. By looking back at the decisions the designers made, and examining how an older style of challenge was brought into a modern game, it allowed me to look back and understand how I experienced the series as a whole. The result is a series of conclusions that I hope will enrich how I look at other games as well.