Diablo II
Seth Sivak


Over the last several decades there have been many attempts to create an over-arching definition of a “game”. In the following chapter I am not going to attempt to pile on yet another, but instead breakdown some patterns in Diablo II that I think make it a great game. There are noticeable structural elements that can be clearly identified, and I hope that at the end of this chapter the reader will have a better understanding as to why Diablo II is one of the best games ever made.

There is no way to adequately analyze and discuss everything about Diablo II (D2) in a whole volume of Well Played, let alone a single chapter. D2 is still in the top 20 best-selling PC games each week almost ten years after it was released on June 29, 2000. The worldwide sales figures for D2 are estimated at close to 5.4 million (1), making it the 8th best-selling PC game of all time (ahead of World of Warcraft: Wrath of Lich King, which has 5.24 million at the time of this writing). There is no doubt that D2 has some of the best staying power of any game ever made.

The game is still being played by tens (if not hundreds) of thousands of people each day. This is no small feat, consider some of the other games released in the year 2000: Perfect Dark (N64), The Legened of Zelda: Majora’s Mask (N64), Deus Ex (PC), Baulder’s Gate: Shadow of Amn (PC), Tony Hawk’s Pro Skater 2 (Playstation) and this was just picking a few of the best-sellers. How many of these games have thousands of fans playing them every day? There is something special about D2 that makes it so replayable. There is something that draws players in and does not let them go.

When first looking at a game like D2, it is important to pull out the moments of fun, these are the actual actions that happen in the game that are enjoyable. Ignoring online-play for now and only focusing on the single player, there is really only six different moments that occur throughout the game. These moments are the actual combat, using a new skill, leveling up the character, exploring an area, finding loot and completing a quest. All of these moments fit into three main categories of mechanics: combat, character building and story. These all appear simple and generic, but they all work together in important ways.

Looking beyond the moments, it is interesting to consider the motivation of the player once the story-based gameplay has been finished. There is a Challenge Pivot Point that occurs when the player takes charge of selecting their own challenges and no longer relies on the game to provide them in a linear fashion. This will be discussed towards the end of the essay along with a brief analysis of The Social Factor, which is so valuable to D2.

Before we jump into an analysis of the moments, it is important to establish a basic structure for interaction in D2 and other games. After playing hundreds of hours of D2, I think the most basic way to explain the core structure is the Challenge – Work – Reward Cycle.

Challenge – Work – Reward Cycle

While analyzing D2, I found that there was a constant pattern that develops around every goal and challenge. This pattern is simple, but becomes much more interesting once consideration is given to the will of the player and the ability for the player to seek out their own challenges. In general the most basic gameplay loop is the game presenting the player with a challenge, the player doing work or using a skill to complete the challenge, and the game rewarding the player based on a scale of how they performed while completing the challenge.

A player is likely to feel compelled to complete the first few challenges that any game throws their way. There is initial interest in exploring any new game, and this is normally due to the money the player spent to acquire the game. However, it is important to note that the challenge needs to be balanced such that the work or skill required does not out weigh the player’s current investment in the game. If the first task that a player is given requires prolonged gameplay, like traversing an entire dungeon, the player is much less likely to complete it. Most well balanced games build this up slowly, working hard to give greater rewards for challenges that require more work or skill. This creates a progression curve.

The increasing ability of the player, and the feeling of satisfaction from completing increasingly difficult challenges, creates a feeling of mastery in the player. This sense of mastery, combined with the feeling of progression and knowledge of the game world will lead to greater investment from the player. In turn it is this investment that drives the player forward to continue to work on challenges of greater depth. This idea of balancing ability level with challenge is one of the pillars of the theory of flow from Mihaly Csíkszentmihályi (2). When done correctly it allows the player to progress without ever feeling that the game is too easy, or getting frustrated because the game is too difficult.

These patterns can be seen in D2 and many other games. With a clear understanding of these structures it is easier to look at how a series of moments can be combined to create a powerful game. A game as deep as D2 does not rely on a single threaded progression curve, but instead allows for several to be woven together and overlap. This complexity means that longer tasks feel incremental, because while working towards the long-term goal there is progress made on short-term goals. To get a better understanding of this we need to look deeper into the moments that actually make up Diablo II.

Suite of Moments

Every gamer has experienced the feeling of a headshot, or that great interception, or beating a difficult boss. These specific moments are what games strive to create. They may not always be fun, but they are always emotional and compelling for the player. These moments usually involve a surprise, a change of status (the saving roll) or a completion of a goal resulting in satisfaction. Distilling these points down, it becomes clear they are finite and granular and the reaction that the player has to something in the game. D2 has six main moments, and when they all flow together they create a perpetual waterfall with each one feeding into the others. There is a clear hierarchy here where the combat and story moments feed into character building, which is why character building becomes the eventual focus of the game. The player gets hooked on the moment-to-moment gameplay and narrative, but stays for the progression of the character.


While playing D2, it is difficult to deny that there is a strong focus on combat. The buttons that the player presses and the actions that take up the majority of the game are focused around this mechanic. This is the necessary moment-to-moment gameplay that engages the player in the world and with their character. All of the story and character building moments either include or are the direct result of combat. This is how player’s gain experience for their character, but it is also how they gain skill at playing the game.

The combat in D2 is somewhat complex. Each different character type has dozens of skills that need to be coordinated and used together to defeat enemies. The act of selecting a target and needing to click on them, or a location near them, is inherently interesting. It requires hand-eye coordination and timing, both are actions that require a certain amount of prowess. There is some level of aptitude involved in choosing the proper skill and using it at the proper time. This is what draws the player into the game and is the most interesting interaction they can experience in the game world. D2 does an excellent job of making the moments of combat very granular. There are small pockets of enemies that appear, and they almost always come running from off-screen at the character (it is just more exciting that way, they become a threat). These short sections of gameplay create fun moments that come at irregular intervals creating surprise and excitement.

As the character gains experience more skills unlock. There is an important difference between combat with known skills and the combat that occurs while the player is learning a new skill. Part of the strategy of the game lies in finding combinations of skills that work together, and knowing when to properly execute them. It is a fun moment when a player discovers a new combination of skills or interesting way of using a new skill. The player will feel smart and more powerful, and player’s character will progress and grow. These two moments are the core interactive component of the gameplay of D2 and feed directly into character building.

Character Building

Experience-based role-playing games are nothing new, and D2 did not do much to innovate on the idea. The factor that makes an RPG different from say, a shooter, is that the focus of the RPG is on the player’s character. The progress of the player is not tracked by the level in the game world or the number of puzzles completed, but by the experience and gear of the character. This means that in the eyes of the player, going through the same game world level repeatedly in an RPG is fundamentally different than that of a shooter. In a shooter, progression is judged by the levels the player completes, but in an RPG progression is judged by the player’s character. Replaying the same level in Halo is similar to leveling the player’s character from 10 to 11 multiple times. RPG players usually only do this with a different type
of character.

There is really two major ways to increase the power of the character, and they are both important accomplishments for the player. The first is to reach the next level, or “level up” the player’s character. This incremental step comes after getting experience from completing quests or defeating enemies and gives the player a strategic choice of where to put a skill point and stat points. This fits perfectly into the progression curve discussed earlier because each level requires slightly more experience than the last one. Leveling up is very important for the player because it can unlock new content in the form of skills. This will allow the player to try out these new mechanics, which can have a drastic impact on the moment-to-moment combat gameplay. This is the most concrete feedback that the player receives about the progression of their character.

The other important moment in regards to character building is getting new loot. How well the character performs is related to the character stats, skills and equipment. Getting a new item can often profoundly change the overall gameplay. Getting loot typically happens as a result of defeating enemies in combat, but can sometimes come as a quest reward. The randomness of “loot drops” is a particularly interesting phenomenon that taps directly into human psychology. Specifically, the work of B. F. Skinner in operant conditioning, which showed ways to model behavior based on reinforcement and response. Essentially, the knowledge that the next enemy might drop the item that the player is looking for is enough to drive the player to keep going after that item. If the item the player wanted dropped from a specific enemy at a specific time there would be no surprise, which really would not be any fun.

Both of the moments related to character building have an impact on how the character performs during combat. However, these accomplishments only come as a direct result of combat or completing quests, which creates a cycle for the player that allows one achievement to feed off another. These moments are specifically centered on milestones that the character achieves, and there is no way for the player to “win” in this regard. While there is a level cap, it requires a near insurmountable amount of time for most players, and due to the random nature of rare item creation, it is essentially impossible to find a perfect set of equipment. This creates a vast amount of open-ended gameplay that becomes important when making the pivot from game-supplied challenges to player-supplied challenges.


One of the most essential elements to D2 is exploration. The levels in the game world are randomly generated with a wide variety of art. Each time the player steps out of the starting town in an Act there is something unknown to explore. The map is not given to the player; they must uncover it by traversing the entire area. This creates urgency in the player to fully explore entire areas. It is not enough to simply travel from point to point, there is the possibility of a rare monster or powerful shrine, and so it is worth the extra time to search. There is a feeling of accomplishment when an area is fully explored and this often works as a solid short-term goal, much like finishing a level in traditional non-RPG games. It is no coincidence that the first quest in the game is to find a cave and explore the entire area to defeat all the monsters. This quest could have easily been to kill 50 monsters, but by making it about cleansing the entire cave, it teaches the player the value of exploration.

The clearest examples of challenges in the game are the quests. These are the narrative drivers of the game and the most powerful tools that the game has to incentivize the player. These are hand-authored pieces of content, which is a stark contrast to the randomized level layout and generated items. This is the piece of the game that makes it feel familiar, like a single-player RPG. The quests are crafted in such a way that the player is always working on at least one at any given time (through normal gameplay). These serve as longer term goals since there are fewer quests than there are game levels and each quests requires the player to be roughly three to five levels higher than the last quest. The player is given a quest early on, with little knowledge about the game world, or their character, but as they pursue the quest they will hit other incremental goals like the moments mentioned before. Each time a new game level is fully explored or the character reaches a new level, the player gets an incremental reward and starts to become more invested in the game. Players seem to respond very well to quest driven gameplay and it is brilliant to put these smaller goals along the way so the player can learn about them and start to understand the value before making the pivot away from quests being the player’s direct goal.

Clearly the completion of a quest is an important moment. This uncovers more narrative and usually opens up more quests. It also usually includes a reward both in the form of experience for the character but also a new piece of loot. Completing quests is usually a highlight and milestone in the game as the player builds investment towards choosing their own goals. The rewards for the quest feed into character building, so while the quests stand as the focus for the early game that long-term goal remains character building.

Example: Overlapping Interest

To make the idea of a suite of moments more concrete here is an example play session for the very first quest in D2. The moments come together to form a Tiered Goal System for the player that includes goals, which take differing lengths of time. At this early stage of the game it is fair to say that the player will experience these moments along the way to their direct goal, which is given by the game in the form of the Den of Evil quest.

The actual individual combat events are not placed in this graph because of the shear amount, but all other moments are included. It is important to note that the long-term goal of the Den of Evil quest is achieved only after experiencing all of the other moments listed. In this particular case I was playing as a Necromancer and I ended up having to explore the entire Blood Moor before finding the Den of Evil. Even if this were not the case, I would have been required to explore the entire Den of Evil before I could complete the quest. The steps in the Den of Evil quest were included because it is interesting to see that even the quests have some incremental goals and feedback associated with them.

The use of a direct goal, given by the game, is a powerful way to get the player invested. The indirect goals are somewhat unexpected at this stage. They are a nice surprise for the player, but the focus remains on finishing that quest. The use of quests to instill the player with a sense of purpose early on is needed to really gear up the investment that the player has in the character and game world. Simply telling the player to reach level four or search for some loot would likely not be good enough at this early stage of the game. Most players would not clearly understand why they would want to reach level four, it is too abstract and the temptation of new loot does not matter much when the player does not understand the importance
of items.

Quests are needed, even in open-ended games, to let the player learn about the world and what they can do in it. The use of a solid narrative resonates with players, and they often accept it and are able to suspend their disbelief to a greater degree. The quest gives the player something familiar in a totally unfamiliar world, even if a player has no idea what the Den of Evil is they can likely guess it is a place with a bunch of monsters and is inherently bad. Who wouldn’t want to cleanse the Den of Evil?

However, the hand-authored quest content eventually runs out, yet even after treading through it on three difficulty levels, players continue to play D2. The reason behind this lies in the pivot from game-supplied challenges to player-supplied challenges.

Challenge Pivot Point

As mentioned previously, the quests in D2 can only bring the player so far. The player will eventually become invested enough in their character that the quests are no longer their direct goal. The player will not get bored using the same skills constantly, doing the same quest for the third time or exploring the same game levels with the same monster, because they are gaining experience towards their character’s next level up. The point where the player’s character becomes their primary motivation is the Challenge Pivot Point. It is when the player will start to “grind” for goals that they choose for themselves.

In the Challenge-Work-Reward cycle discussed earlier, the burden of supplying the challenges rests on the game. The quests and story provides hand-authored content that the player can experience in a very linear fashion. The player has initial investment in the game from purchasing it, and the player is sent on a game controlled linear path of goals from the start. At the Challenge Pivot Point, the game is no longer in control. This is the point when the player is now in charge, seeking his or her own challenges and goals. It can be anything from reaching maximum level to completing a certain item set, and in D2 it is almost always related to character building. The character building provides the most open-ended content, and the player can start to pick and choose what they find important for their character.

This is the basis for all achievement-type mechanics. The game no longer provides a set of linear goals, but instead just provides a huge variety of goals and challenges. Normally, a player would find these choices overwhelming, not quite understanding what consequences might occur or how much work is required for a certain challenge. However, when they are at the Challenge Pivot Point, the player is quite experienced in the game and is also invested enough to want to make these choices.

The player is introduced to these challenges and moments early on, but they are not the focus. They are just a nice incremental bonus. The player is not expected to find them meaningful until they have fully grasped the depth of the gameplay. The excellent use of quests in D2 prepares the player for the end game, where the story no longer matters as much to the player, but instead it is their character that takes over. Blizzard has used this cycle of quests providing the bridge to the character-focused end game in both D2 and World of Warcraft

The Social Factor

It is impossible to deny that the multiplayer in D2 is probably the most groundbreaking mechanic in the game. D2 utilizes the feeling of adventuring as a group to help support the player’s investment in their own characters. The characters are their representation to other real-world people, and therefore reflect on their real-world selves. Playing with friends also adds instant investment for the player and gives the player something familiar early on.

Social pressure has an interesting impact on games. Even if a player is bored of the game, or has no quests to complete, they will likely still help out a friend if asked. This is due to the fact that the player is invested in that relationship with their friend, much the same way they become invested in their character. Players will retread content over and over if it will further their relationships with friends. Every single moment mentioned above becomes better when shared with friends, and there are new dynamics that become important when friends are involved.

When playing with friends the Challenge Pivot Point changes to be a pivot between the game created challenges and those presented by a friend. These include both helping a friend and engaging them directly in competition. The reason this transition is so easy relies on the fact that the player has a strong investment in the relationship with their friend, so it is easy for that to overtake their investment in the game.

The social investment is always high and will likely often take priority over other challenges. This can obviously change based on the relationship of the player and friends, but for the most part the social gameplay will always trump the rest. However, due to the limited amount of time that players can actually play together, the Challenge Pivot Point is still very important, and will often be accelerated because investment in the character becomes much more personal when other people view it as a representation of the player.

D2 does allow for directly competitive multiplayer through dueling, but this is a fraction of the overall multiplayer experience. However, there is certainly indirect competition between friends trying to gain levels faster or complete more quests. The social factor in D2 adds a complex layer of competition and teamwork. Players can advance faster by working together, but then they must share the rewards.

It is impossible to ignore the social factor in D2 and it is very obvious that it adds replayability to the game. Players will continue to play because their friends play. This has become the backbone of many massively multiplayer online games and games on social networks. The goal of these games is to create a social environment that the player will want to go to spend time with their friends.


D2 really excels at creating investment that feeds into open-ended content allowing for huge amounts of playing time. This feels so effortless and seamless; the player is whisked along on quests until they understand the game enough to actively seek out ways to make their character better. This is compounded by the added social mechanic of helping out (and competing with) friends along the way. D2 has such depth that by analyzing the underlying structure it feels somewhat simple, but it is impossible to discount the difficulty of balancing these mechanics and the sheer amount of hand-authored content that the game includes. The use of the Challenge-Work-Reward cycle to offer players familiar narrative quests is used perfectly to bring the player to the Challenge Pivot Point where the player decides to take control. That level of investment in any game is rare, and that is why D2 is still so impressive even after a decade.


1. VGChartz, http://www.vgchartz.com/worldtotals.php?page=1&results=50&name=diablo, Accessed May 2010

2. Flow: The Psychology of Optimal Experience. Mihály Csíkszentmihályi. Harper Perennial Modern Classics, July 2008.