Diablo 2 Game Design Document

After Diablo's success, Blizzard North moved on to create their most ambitious game ever, a bigger and better Diablo with more heroes, monsters, quests, and loot. But it didn't happen overnight. It took them months to regain their mojo back and return to the full swing of development.

Gaining Back the Mojo

During the creation of Diablo, the team experienced a grueling four-month crunch that drained their spirits later. After the release of the game, they were all burn-out, and they only want one thing - no more crunches.

The team decompressed and moved back to the normal 9 to 5 work schedule. They relaxed and played hockey. For three months, they were not actively developing, just bouncing ideas about what to do next.

They do not want to go back to Diablo right away. Instead, they aim to make a new game.

During this stage, they were providing support for the first game, and they witnessed the rampant cheating that happened in the game. They started to see the many flaws present in the original. And by working on the patches, they realized the many areas for improvement.

What does a new Diablo look like without these flaws? How can we make a better sequel? This is the start of the inspiration as they regain back their mojo. And one day, they no longer felt burn-out.

Work for Diablo II started in 1997, with the first six months being more relaxed. The founders have the following roles:

David - head of software development
Erich - head of the character artists
Max - head of the background artists

Diablo II Design Document

Unlike the first game, Diablo II does not have a formal design document. Instead, what they have is a two-to-three page of wish list items, most of which came from their desire to make a bigger and better sequel.

The Top Priority

The highest priority in their wish list is to fix the rampant cheating. This led to the team's decision for a client-server game. If you are going to do multiplayer, your characters have to be saved remotely.

Players still have the option to play offline or do multiplayer locally.

The second priority of the team is to improve the character classes. They will make more and make them better.

The Full Wishlist

With the first and second priorities identified, the team added the remaining goals for Diablo II.

Secure gameplay via a client-server game
Five character classes instead of three.
Make Diablo's world larger. Have four towns instead of one.
More monsters, gears, weapons, and spells.
A more 3d look for the game.
Variations on the character's appearance
No loading when moving across zones in the game
Factor the story into the game from the very start. Impact on quests.

The Plan

With the wishlist above, the team planned to complete the game within two years of development. They were planning to make the game four times larger than the first, with only two times the work effort.

Design of the Character Classes

The team decided to change their approach for the classes in Diablo II. In the first game, the player's starting class can become anything. The hero can find and use skill books even if they are not optimal for him.

For Diablo II, the team decided to use fixed archetypes, well-designed heroes that cater to specific gameplay. They will also create exclusive skills and weapons for these classes.

During the lifetime of the game's development, the sequence in which the classes were designed and developed is as follows.

Amazon
Paladin
Sorceress
Necromancer
Barbarian

3D vs. 2D

The first Diablo is a beautiful 2D game. For the second Diablo, the team wanted to make a 3D game.

For a while, the developers researched several options, even creating a mocked-up 3D engine. They also studied various voxel systems.

However, they soon realized that with Diablo, you could have a large number of monsters and heroes fighting on the screen, with a plethora of magic, spells, and curses flying around. At this stage of technology, 2D is still the only way to get eight characters and lots of monsters and missiles all interacting on the screen without slowing the game into a slideshow.

The team started with a screen resolution of 640x480, which would be enhanced in the future upon the release of the DLC, Lord of Destruction.

With some craft and smarts, they were still able to make the game look 3D, though, via the perspective mode. So, all those stairs you used in the game, they were not really elevated. They are all flat.

Regarding the appearance of the characters and monsters, they were created to appear 3D. Each of them was rendered from many different angles, eight for the monsters and sixteen for the player characters. Every attack and move is captured and rendered.

Paper Doll System

In the first game, there is not much variety on how the heroes look like, even after changing their armor or weapons. With the new game, the team wanted to show hundreds of varieties of character appearance.

They achieve this by a paper-doll system where the hero model will show the actual armor or weapon being worn.

No Loading

Diablo has a loading screen whenever you move up or down a dungeon. The team wanted to eliminate this, and they succeeded in doing so. The only instance a loading will happen is when the hero moves between acts.

This was achieved by detecting the location of the character. The terrain beyond the monitor is rendered only when a player is within a specific range. This is similar to how the monsters react to the hero only when within a certain distance.

Creation of the Skill Tree

In the first Diablo, all characters can acquire and learn any of the available 28 skills. The team initially decided to follow the same approach for Diablo II - the heroes would find books of skills that are common to all.

However, they decided to move into Skill Trees to differentiate the various heroic archetypes and encourage replayability. Using a new class gives the feeling of playing a new game. The team got the inspiration for the skill trees from the strategy games, especially from Master of Orion.

There will still be variety even if two players use the same class. Each class has three groups of skill trees, which they can specialize in. Hence, you might have a Necromancer that uses poison attacks, and another one that relies on summoning monsters.

Since the maximum level of the game is 99, it is impossible to acquire and level-up all the skills for a single class, contributing to the game's variety and replayability.

The Diablo II Crunch

With the features well-defined and the priorities identified, the team started to crunch. It began in May 1999. They were working from twelve to sixteen hours per day, seven days a week.

Their original goal - deliver Diablo II by December of 1999.

This situation is very similar to the development of the first Diablo. However, this time they were going to miss their deadline and would be given an extension to polish the game.

Losing the Source Code and Assets

During the last few days before completing the game, a disaster happened in the development that could have led to a terrible situation for them. However, they got lucky, and it was averted.

In those days, Microsoft was still a big name when it comes to development languages and tools. Today, this is no longer the case, but during that time, Microsoft Visual Source Safe is popular. VSS is a centralized code repository, where you have to check-in and check-out code.

In the late spring of 2000, a new hire pulled out a disk drive from a server computer. He didn't know that this is the VSS server of the team. He tried to return the disk drive, but it has been fried. This disk drive contained the repository of Diablo II.

This could have led to the loss of Diablo II from the gaming world. But the team worked together to reconstruct the game piece-by-piece. They succeeded, however, the original files were gone - original assets and source code, which could have been useful in the future for a game remaster.

Diablo II Goes Gold

After several months of crunch and almost losing the whole game, the team finally delivered the Beta in March of 2000. Three months later, the game went gold on June 15, 2000. The game is done!

A few days later, on June 28, Diablo II is already for sale on game stores.

The Triumph of Diablo II

In the first 24 hours after the game released, Diablo II sold 184,000 units. One week later, it sold one million units. And six weeks later, two million units. Diablo II broke historical records and became the fastest-selling game of all time in the year 2000. It was a worldwide hit and won many awards, including Game of the Year.

After one year, Diablo II sold more than four million units.

As of 2010, it was still in the top ten list of best-selling PC games.

And that is just on the sales. The true achievement of Diablo II is in being one of the best games ever to exist. There is nothing like it before, and nothing like it afterward.