Transcript THE ART OF Puzzle Game Design

THE ART OF
Puzzle Game Design
Scott Kim & Alexey Pajitnov
March 15, 1999
Game Developers Conference
These are presentation slides from an all-day tutorial given at the 1999 Game Developers Conference</A> in San Jose. This copy of the
slides was taken from www.scottkim.com/articles. All screen shots are copyrighted by the respective game publishers.
Puzzles
Part of many games.
 Adventure, education, action, web
 But how do you create them?

Whether you are designing levels for an cartridge-based action puzzle game, creating puzzle templates for a CD-ROM puzzle anthology,
adding puzzles to an adventure game, or designing an educational game, you need to know how to design good puzzles.
Good News / Bad News
Mental challenge
Marketable?
Nonviolent
Dramatic?
Easy to program
Hard to invent?
Growing market
Small market?
The good news is that puzzles appeal widely to both males and females of all ages. Although the current market is small, it is rapidly
expanding, as computers become a mass market commodity and players demand familiar family games.
Outline
Types of Puzzle Games
Examples: Pipe Dream, Honey Way, Lineman
Examples: Fool, Incred Machine, Puzzle Zone
Case Study: Jesse’s Strips
Case Study: Charlie Blast’s Territory
Case Study: Scott Kim’s Puzzle Box
Exercises: Idea Invention, Word Sokoban
We’ll start by surveying examples of outstanding puzzle games. Then Alexey and I will go into detail about some of our current projects.
I’ll describe the eight steps in the puzzle design process. Finally we’ll split into groups of five people each and do projects.
Types of Puzzle Games
What every puzzle
designer should know
Here are four basic ways to categorize the types of possible puzzle games.
Scott Kim
Varieties of Play Activity
There are four types of play. Noninteractive experiences include books and movies. A Toy has no set goal. A Puzzle has a goal: find the
solution. The goal of a Game is to beat another player. Each type of play builds on the previous type: a puzzle should first be a good toy.
Genres of Puzzle Games
Action puzzle games have time pressure and a way to fix mistakes. Story puzzle games have puzzles that advance the plot. Strategy puzzle
games are based on multiplayer games. Construction puzzle games let you build something. Pure puzzle games are just puzzles.
Player Motivation
Different people play puzzls for different reasons. Some see puzzles as metaphors for spiritual journeys. Puzzle fans like the challenge of
finding the answer. Tetris and Solitaire players use puzzles as light distractions. People buy Disney titles for the familiar characters.
Modality
People who play puzzles tend to prefer one of three basic types: Word, Image or Logic puzzles. Each of these types of puzzle uses a
different mode of thought. Of course some puzzles combine more than one mode. For instance, Hangman is a logical word game.
EXAMPLES
Pipe Dream
One concept,
Three designs
Here are some of our favorite puzzle games (other than ones we have designed). We
chose examples that cover the full range of issues that arise in designing puzzle games.
Alexey Pajitnov
Pipe Dream

The simplest
construction on the
regular grid is the path
from one cell to
another
Although Pipe Dream could be classified as an action puzzle game, at its heart it is a construction game. Other examples of constructive
puzzles are: Lemmings, The Incredible Machine, Puyo-Puyo.
Pipe Dream

After obvious
straightening of the
path we realize that we
need a very simple set
of pieces:
To make the concept of constructing a path more suitable for a computer game we restrict lines to a square grid.
Pipe Dream
4
corners
2 two lines
1 cross
Seven pieces is a magic number. Tetris has seven pieces. Psychologists have found the human short term memory can hold about seven
things (plus or minus two). That is why 7-digit telephone numbers are so much easier to remember than 10-digit numbers.
Pipe Dream
CONCEPT:

Build a path from one cell to another using
one-cell elements
So this is the concept.
Pipe Dream
DESIGN ELEMENTS:
 Playing field
Regular grid 7x10
 Objects
4 corners, 2 lines, 1 cross
 Rules
Source of pieces: 5-cell stack
 User interface
Click to place; replace takes time
 Scoring, levels Nothing special
To make a game, we need to specify these design elements.
Pipe Dream (original)
CONCEPT: Build a path from one cell to another
using one-cell elements





Playing field
Objects
Rules
User interface
Scoring, levels
Regular grid 7x10
4 corners, 2 lines, 1 cross
Source of pieces: 5-cell stack
Click to place; replace takes time
Nothing special
For the original Pipe Dream, published by LucasFilm Games, these were the design decisions.
Pipe Dream (Microsoft bonus level)
CONCEPT: Build a path from one cell to another
using one-cell elements





Playing field
Objects
Rules
User interface
Scoring, levels
Regular grid 7x10
4 corners, 2 lines, 1 cross
Sliding tiles
Click to slide, restriction on drawn path
Nothing special
But other games can be built based on the same concept. The Microsoft Entertainment Pack version of Pipe Dream includes a sliding tile
variation as its bonus level. Quite a good game.
Pipe Dream (Lucasfilm bonus level)
CONCEPT: Build a path from one cell to another
using one-cell elements





Playing field
Objects
Rules
User interface
Scoring, levels
Regular grid 7x10
4 corners, 2 lines, 1 cross
Falling tiles (like Tetris)
Control while falling
Nothing special
The original Lucasfilm version includes a Tetris-like variation of Pipe Dream as its bonus level. Very hard game; it is almost impossible to
construct paths of more than about five tiles.
Honey Way
CONCEPT: Build a path from one cell to another
using one-cell elements





Playing field
Objects
Rules
User interface
Scoring, levels
Variable hexagonal grid
All corners and lines, 3 crosses
Preset sources, crosses and obstacles
Drawing the path as freehand
Nothing special
For the Mind Aerobics daily puzzle on the Internet Gaming Zone, Alexey created a simpler game based on the same concept. The grid was
changed from square to hexagonal, the player could build paths freely by drawing lines, and sources, crosses and obstacles were given.
Honey Way
The hexagonal grid suggested the theme: bees and honey.
Honey Way
The player tries to construct a line of honey from one honey blob to another by drawing lines from one cell to another.
Honey Way
The path must pass through every cell of the grid once, crossing over itself at the flowers in the directions indicated by the petals. Here is a
complete solution. It looks complicated, but the hexagonal grid is actually more forgiving for path construction than a square grid.
Honey Way
Dangerous bees complicate some of the puzzles.
Lineman
CONCEPT: Build any cyclic path
using one-cell elements





Playing field
Objects
Rules
User interface
Scoring, levels
Regular grid 10x10
4 corners, 2 lines, 1 cross
Pieces appear on field; loops collapse
Click to rotate pieces in place
Nothing special
Lineman, from the Russian Six Pack (Interplay) uses the same seven objects but different rules. Pieces appear directly on the playing field
and can only be rotated, not moved. The goal is construct loops, which collapse, not paths from one place to another. Excellent game.
EXAMPLES
Fool’s Errand, Incredible
Machine, Puzzle Zone
Three games,
Three genres
Here are other puzzle games that demonstrate some of the design challenges in other puzzle game genres.
Scott Kim
The Fool’s Errand
Integrated story, puzzles, art
 Idiomatic puzzles
 Metapuzzle

Created solely by Cliff Johnson in the 80s, The Fool’s Errand is an integrated work of art. Each puzzle links with a tarot card and story
segment. The bold silhouette art style looks good on a small screen. Each puzzle unlocks part of a larger unifying “meta-puzzle”.
The Incredible Machine
The Incredible Machine (TIM) is the best construction puzzle game. There are three important design decisions. Decision 1: allow the
player to build things. SimCity, shown above, allows construction, but does not give the player a fixed goal and is thus a toy, not a puzzle.
The Incredible Machine
Decision 2. No realtime decision making. In contrast, Lemmings, shown above, requires players to solve the puzzle by repositioning
lemmings while they are walking around. In The Incredible Machine, building and running machines happen in separate modes.
The Incredible Machine
Decision 3: Player authoring. In contrast, Marble Drop, shown here, has separate build and run modes, but does not allow the player to
construct original puzzles. Instead, all the puzzles come preconstructed, which allows Marble Drop to have beautifully rendered screens.
The Incredible Machine
In The Incredible Machine, players can build their own puzzles in a separate freeform construction mode, separate from puzzle mode. The
goal of this particular puzzle is to get all balls into all the aquariums using a motley collection of ropes, pulleys, ramps and other devices.
The Incredible Machine
Physical simulation
 Player authoring
 Integrated controls

The designers of TIM did a brilliant job of including a broad range of play elements that all interact with one another within a rich physics
model, while keeping the user interface simple and obvious.
Puzzle Zone
The Puzzle Zone on America Online [editor’s note: now on boxerjam.com] is a good example of an online puzzle. Following the model of
newspaper puzzles, Puzzle Zone delivers four new puzzles every day. The puzzles add new twists to familiar word games.
Puzzle Zone
Flexicon, shown above, is a twist on a crossword puzzle. The problem with crossword puzzles on computer is that the screen is too small
to hold a large puzzle. The solution here is to save space by overlapping four rectangular regions, only one of which is visible at a time.
Puzzle Zone
Strip Search adds new twists to the familiar word search.: The theme here — Joes — was inspired by the topical event of Joe Dimaggio’s
death. Found words appear in order of length, giving the player a hint. When all words are found, the leftover letters form a witty phrase.
Puzzle Zone
Finally, the Puzzle Zone also includes elements that build community and encourage players to keep coming back: message boards, high
score boards, and a place to buy branded merchandise.
Puzzle Zone
Familiar puzzles
 Daily editions
 Online community

The puzzles in Puzzle Zone are somewhat mundane and obvious, but that is not a bad thing. By using familiar puzzle types, the Puzzle
Zone lowers the barrier to entry. Furthermore, word games require very little data to be downloaded, so play is snappy.
CASE STUDY
Jesse’s Strips
Recent design experience
with 3 aha’s
Jesse’s Strips, designed by Alexey Pajitnov, is one of a number of image-based puzzles
from Pandora’s Box, a forthcoming title from Microsoft.
Alexey Pajitnov
Jesse’s Strips
CONCEPT

To make jigsaw puzzle using long narrow
pieces (strips)
One of the members of the Pandora’s Box team suggested the concept.
Jesse’s Strips
PROBLEM

The playing field is too messy
The problem with long skinny pieces, however...
Is that the playing field quickly gets messy.
Jesse’s Strips
Problem:
The playing field is too messy
Solutions:
no

no

??

Stack the pieces
Separate picture and pieces in different windows
Enlarge the space for more than one screen
no

Yes!

Scroll the playing field
Paginate the playing field
I considered many possible solutions before hitting on the idea of spreading the pieces across several different pages.
Jesse’s Strips
First AHA:
To make multiple pages and repeat the picture in
progress on each of them, distributing the pieces.
This was the first Aha.
Jesse’s Strips
Problem:
Player does not understand what happens
when the pages switch
Solutions:
no

no

no

Yes!

Change picture position
Change background look (color, texture)
Use animation for changing pages
Change the picture in progress.
But this insight raised another problem...
Jesse’s Strips
Second AHA:
To emphasize certain color for the picture on each page;
to do the same with the pieces on the page.
Which in turn required a second Aha.
Jesse’s Strips
Problem:
We need to move the pieces from page to
page now and User Interface become too
complicated
Solutions:
Yes!

Yes!

Work on UI
Connect the piece movements with rotations
The final insight was motivated by wanting to keep the user interface simple. Instead of separate commands to rotate pieces and changes
pages...
Jesse’s Strips
Third AHA:
To move the piece to the next page together with the 90
degrees rotation.
The two things happen together. This is a good
example of how the difficulties in realizing a
particular puzzle concept can guide the designer
toward novel solutions. [Editor’s note: the final
published version in Pandora’s Box works
differently.]
CASE STUDY
Charlie Blast’s Territory
Adding action to a classic
computer puzzle game
Charlie Blast’s Territory is a game for the Nintendo 64 published by Kemco. Kemco hired Realtime
Associates to develop the game; they in turn hired Scott to assist in game design and level design for the
puzzles. This example highlights some of the techniques he used in level design.
Scott Kim
Sokoban
Classic, widely copied
 Simple rules
 Deep puzzles
 Fits the medium

Charlie Blast is based on the classic puzzle game Sokoban, which is one of the most widely copied computer games. It has simple rules
that are easy to program, yet has deep gameplay. It works well on low-resolution displays with simple arrow controls, such as GameBoy.
Changing Sokoban
Pieces: Bombs, shapes, pictures
 Board: Breakaway, ice, bumper
 Moves: Push two, pull not push
 Goal: Push to hole, arrange bombs
 Play mode: Multiplayer, action

One of the most common ways to create a new game is to change an existing game. Here are some ways to change Sokoban.
Charlie Blast’s Territory
Based on Sokoban
 For N64, American audience
 Uses 3D graphics
 Adds action elements

For Charlie Blast’s Territory Kemco decided to pump up the 3D action elements of the game by using 3D perspective, moving camera,
animated main character (Charlie Blast), and adding action elements.
Challenge: Add Action Features
Jumping
 Autodetonator
 Moving platforms, spikes
 Multiplayer competitive mode
 Not included: damage

We added common action game features like jumping, moving platforms, moving spikes, and a multiplayer competitive mode. We did not
include damage points, because that would have shifted the emphasis of gameplay too far in the direction of dexterity, not puzzle solving.
Challenge: Add Other Features
Bombs & Detonator
 Objects: TNT crates, blocks
 Tiles: breakaway, ice, trampolines
 Not included: enemy characters

Features like bombs, blocks and breakaway tiles add depth and variety to the underlying Sokoban game. Of course features interact with
each other. TNT crates and blocks were introduced specifically to complement the jumping ability.
Bombs
Here’s how bombs work. A 1 bomb blows up itself. A 2 bomb also blows up the four adjacent squares. A 3 bomb blows up a larger
diamond region. The detonator and TNT act like a 2 bomb. You can light pm;u a detonator, and you can jump only over TNT.
Bombs
The goal of every puzzle is to arrange the bombs so that when Charlie lights the detonator, it triggers a chain reaction that blows up all the
bombs. Suppose Charlie lights the detonator in this configuration. Which bombs will not blow up?
Bombs
Here’s the answer. The only bombs that don’t blow up are the 1 bomb at right, which is too far away from a 2 bomb, and the 2 and TNT
bombs in the lower left, which touch another 2 bomb diagonally.
Challenge: Design Levels
60 levels = 6 groups of 10
 Easy to hard within a group
 Each group features different devices

The bulk of my time was spent designing the 60 levels, structured as 6 ramps of 10 puzzles each. Puzzles within a ramp start easy and get
harder. Each ramp has a different visual theme and emphasizes a different mix of features, to keep the game from getting too repetitive.
Building Levels
Tell a Story
 Paint a Picture
 Create a Mood
 Use Math
 Exploit features
 Lay a Trap

I used many different strategies for coming up with ideas for levels, so that there would be a wide variety of puzzle types. Here are six of
my strategies. Following are examples of how I used each strategy to design a particular level.
Building Levels: Tell a Story
#17 Run Like Crazy
Some puzzles are structured as a linear sequence of events. For this puzzle, Î started by drawing a board that wraps a long narrow corridor
into a small space.
Building Levels: Tell a Story
#17 Run Like Crazy
This puzzle features an autodetonator, shown in red here, which blows up automatically in a preset amount of time unless you touch it to
reset it. The basic drama of this puzzle is that you must run to the autodetonator, then push it back a long way so it blows up a bomb.
Building Levels: Tell a Story
#17 Run Like Crazy
I then compounded the puzzle by adding obstacles along the three legs of the journey. Moving spikes that raise and lower out of the game
cause you to have to wait a bit before you can get to the autodetonator -- frustrating when you have to get there quickly.
Building Levels: Tell a Story
#17 Run Like Crazy
Next you must push the autodetonator onto a moving platform that travels slowly to the right, then push it off. Again, timing is critical if
you are to execute this move before the autodetonator blows up.
Building Levels: Tell a Story
#17 Run Like Crazy
I added one more spike in the right leg of the journey..
Building Levels: Tell a Story
#17 Run Like Crazy
Finally there is the end game. One bombs only blow up themselves, so the ending position must be an autodetonator surrounded by one
bombs. Because two of the 1 bombs are against walls they cannot be pushed away from, there is only one possible ending position.
Building Levels: Paint a Picture
#48 Ice Rink. Initial pattern.
Another way to invent a puzzle is to start with a pretty pattern, then try playing it. Here are three opening positions I considered for the
puzzle Ice Rink. They look similar, but behave very differently. You cannot stop moving on ice until you hit a wall or reach solid ground.
Building Levels: Paint a Picture
#49 Diamond. Initial pattern.
Here are three patterns I considered for a puzzle called Diamond, which features a patch of ice surrounded by solid ground. After drawing
the opening patterns I played them to see if they could be solved. If they were not solvable, I then had to decide how to modify the pattern.
Building Levels: Paint a Picture
#60 The… Final pattern.
For the final puzzle I decided to aim for a pretty final position that would spell the word “End”. This is what I originally hoped for..
Building Levels: Paint a Picture
#60 The… Initial pattern.
The actual final puzzle required many modifications to the boards and pieces to make sure that the puzzle only had one solution. Shown
here is the final beginning position.
Building Levels: Paint a Picture
#57 Pinball. Overall picture.
One of the features of Charlie Blast is bumpers, which rebound bombs pushed into them. Bumpers reminded me of pinball bumpers, so I
built this puzzle to look like a pinball machine, complete with a moving beltway for returning a queue of balls into play.
Building Levels: Create a Mood
#16 Long Haul
Some puzzles create distinct moods. Long haul, for instance, creates a frantic suspenseful mood as you must run further and further away
from an autodetonator with a very short fuse in order to reposition bombs that are further and further away.
Building Levels: Create a Mood
#16 Long Haul
It is easy to see that the autodetonator and 1 bomb cannot move, so the solution must be to create a chain of 3 bombs reaching from one
end to the other.
Building Levels: Create a Mood
#16 Long Haul
Or is it really that easy? A bit of analysis will show that the previous solution cannot be achieved, so a modified chain like this is
necessary.
Building Levels: Use Math
#39 Peninsula
Puzzle designers often mine mathematics for ideas. Shown above is a puzzle based on the mathematical idea of a tour. The goal is to draw
a closed path that visits every square once, using all the red lines. The unique solution is shown at right.
Building Levels: Use Math
#39 Peninsula
I decided to make a puzzle for Charlie Blast that used the idea of a tour. Suppose the tiles above are all breakaway tiles, which means you
can only step on them once. How would you push all three one bombs off the bottom edge of the square? One solution is shown at right.
Building Levels: Use Math
#39 Peninsula
After a bit of work I came up with this more difficult tour puzzle. The goal is to push all three 1 bombs off the bottom edge of the square
by walking a single path. The unique solution requires that you visit every square exactly once.
Building Levels: Use Math
#39 Peninsula
Here’s the final puzzle. The purple electric bombs act like 2 bombs, except if one electric bomb blows up, the other also blows up. Since
the electric bomb along the bottom edge cannot be pushed up toward the 1 bombs, the three 1 bombs must be pushed down to surround it.
Building Levels: Exploit Features
#30 Moving Ground
Another strategy is to exploit a feature. Shown above are two states of the same board, built entirely of moving platforms. The tall
rectangles move left and right, while the wide rectangles move up and down. The green arrows show how the 2 bomb could be pushed.
Building Levels: Exploit Features
#30 Moving Ground
Here is the final puzzle. The ground at the bottom is stable, while the ground at the top is moving. The goal is clear: build a chain of
bombs between the immovable detonator at left and 1 bomb at right. But getting there requires a hair-raising ride around the platforms.
Building Levels: Exploit Features
#30 Moving Ground
This puzzle is easier to analyze if we collapse time and push all the platforms together so all adjacencies are present at the once. The green
arrows show all paths that bombs can follow as they move around the platforms. Removing the dead ends, we discover the loop at right.
Building Levels: Lay a Trap
#58 Tadpole
Finally, puzzles can trick you into pursuing the wrong line of reasoning. For the puzzle Tadpole, I started by observing that a puzzle
involving a 2 bomb, detonator and six 1 bombs must end with the 2 bomb and detonator surrounded by the 1 bombs.
Building Levels: Lay a Trap
#58 Tadpole
With that analysis in mind, this puzzle appears to be simple: push the autodetonator into the pocket, seal the opening with a 1 bomb, then
sit back and watch the fireworks.
Building Levels: Lay a Trap
#58 Tadpole
By adding a couple of spikes I gave the puzzle a new wrinkle.
Building Levels: Lay a Trap
#58 Tadpole
Now you can only push the autodetonator as far as shown above by the green line. You cannot push the autodetonator any further because
the spikes prevent you from getting to the square to the right of the final position of the autodetonator.
Building Levels: Lay a Trap
#58 Tadpole
The real solution requires that you rebuild the entire hexagonal pattern of 1 bombs up and to the right one square.
Building Levels: Lay a Trap
#58 Tadpole
To complete the puzzle, I added some blocks and breakaway tiles.. These complications add difficulty to the puzzle, but are not integral to
the central theme of the puzzle.
CASE STUDY
Scott Kim’s Puzzle Box
Creating a monthly puzzle
for a children’s web site
The second case studies a monthly puzzle called Scott Kim’s Puzzle Box, which Scott created for the kid’s
online service Juniornet. This example highlights issues in designing puzzles for the web.
Scott Kim
JuniorNet
Safe online place
 For kids 3-12
 Content partners
 Subscription
 CD-ROM

Juniornet is an online service that gives kids a safe, fun, rewarding, and ad-free experience. Content comes from such well known brands
as Highlights and Weekly Reader. Subscribers receive a CD-ROM, with more frequently updated content streamed across the internet.
Scott Kim’s Puzzle Box
Monthly, weekly
 Player authoring
 Fun, educational
 Learning styles
 Branded

My feature on Juniornet is an original content area called Scott Kim’s Puzzle Box, which delivers.a new collection of puzzles every
month. The type of puzzle changes from month to month. Players can create their own puzzles, some of which are posted on the site.
Design Challenges
 Adapt
existing physical puzzle
 Structure for efficient production
 Player authoring
Producing a rich puzzle experience on a monthly schedule posed several design challenges..
Challenge: Adapt Hiroimono
 Hiroimono
=
“Things Picked Up”
 500 years old
 From Japan
The puzzles are adapted from existing puzzles. For instance, the April puzzle is based on Hiroimono, a popular puzzle from Japan
traditionally played with Go stones.
Changes to Hiroimono
 Animated
characters
 Specify beginning
 Clear motivation
 Embody the rules
To make Hiroimono friendlier to kids I embodied the rules in the characters of a dog that is eating pet treats, and a cat that prevents the
dog from backing up in the direction it came. Even with words, kids could be attracted to the game and have a sense of what it is about.
Challenge: Efficient Structure
FIXED FORMAT
Monthly puzzles
 Kid’s puzzles
 Letters
 Puzzling Times
 My Puzzles

In order to keep production costs reasonable, I planned a modular structure that would allow most of the site to stay the same from month
to month. These basic features are always the same.
Structure
4 TEMPLATES/YEAR, 3 VARIATIONS EACH
Pet Tricks
Tangrams
High Flyer
Patchwork T.
House Painter Glass Tan.
Arrow Maze Drum Circle
Number Maze Bell Circle
Shape Maze
Rap Circle
The type of puzzle changes every month. But instead of creating 12 different puzzle engines, I create only 4 engines for the year, then
reuse each engine 3 times with minor variations.
Structure
15 MONTHLY PUZZLES, 24 KID’S PUZZLES
Every month I deliver 15 puzzles that I created, and 24 puzzles that kids create.
Structure
Fixed Format
Puzzle engines
Variations
Month puzzles
Kid’s Puzzles
Production is structured so that the most difficult pieces to build change the least often. Templates change only once every three months.
The monthly template variations require only art changes. Finally, puzzle specification requires only compact text files.
Challenge: Player Authoring
Simple pieces
 No interdependence
 Random puzzles OK
 Solve before submit

Players can create and submit their own puzzles. In order to keep puzzle creation kid friendly, I chose puzzles that are relatively easy to
author. And I require that players solve their puzzles before submitting them, so I don’t receive puzzles that don’t work.
TECHNIQUE
Puzzle Game Design
In eight easy steps
Now that we’ve seen two very different examples, what can we say about puzzle design in general?
Scott Kim
The Eight Steps
1. Inspiration
2. Simplification
3. Construction Set
4. Rules
5. Puzzles
6. Testing
7. Sequence
8. Presentation
Here are the steps in designing any puzzle game. The first four steps sharpen the concept into a design specification; the last four steps
bring the concept into reality.
1. Inspiration: Previous Game
Where do ideas come from? Here are six ways to get inspired. First, you can look to a previous game. Tetris was inspired by a
noncomputer game called pentaminoes, and in turn inspired Welltris and other Tetris spinoffs.
1. Inspiration: Technology
1. Enable nonphysical moves (Tetris)
2. Algorithmic hint, create, analyze, enemy
3. Enforce the rules (Sokoban)
4. Undo, record moves (Solitaire)
5. Structure the experience (Lemmings)
6. Instruction (Chess)
7. Bells and whistles (Battle Chess)
8. Online play (NY Times crossword)
If you are going to put a puzzle on computer, there should be some gain. Many computer puzzle games do things that could never be done
in a physical puzzle. But even if the puzzle is physically possible, there are many other ways the computer can enhance gameplay.
1. Inspiration: Play Mechanic
Endorfun was inspired by the play mechanism of a colored cube rolling on a square grid.
1. Inspiration: Subject matter
Start with something you love
 Express it as if it mattered
 Give each puzzle a memorable identity
 Like a good song, a good puzzle has soul

Like songs, puzzles can be inspired by real life. Stephen Sondheim: A good clue can give you all the pleasures of being duped that a
mystery story can. It has surface innocence, surprise, the revelation of a concealed meaning, and the catharsis of solution.
1. Inspiration: Story
Story puzzle games like Myst are built around story line, character, setting, and mood.
1. Inspiration: Art
The story game Obsidian started as a series of concept sketches for characters and environments. Story and puzzles came later.
2. Simplification
The second step is to whittle the concept down to manageable size. Say we wanted to make a puzzle based on the tricky core skill of
parking a car in a crowded lot. We eliminate irrelevant details and make pieces uniform by conforming them to a square grid.
3. Construction Set
Programmer: reusable code
 Rule designer: tweak rules
 Level designer: build levels
 Player: build levels

The only way to test a puzzle concept works is to play it. So the next step is to build a construction set that makes it easy to build puzzles
of a certain type. Sometimes a paper prototype is adequate. Once the rules are set, other people can use the construction set to build levels.
4. Rules
Board — grid, network, irregular, none
 Pieces — shape, image, attribute, supply
 Moves — sequential, side effect, primary
 Goal — exact match, partial, condition

Now it is time to write a detailed design specification. Most puzzle game specs will describe puzzles in terms of board, pieces, moves and
goals. In addition a design spec may also cover the user interface, scoring, story, art, sound and other aspects of production.
5. Puzzles
Schematically, a puzzle challenges the player to get from a problem to a solution.
5. Puzzles
But of course the path is never simple. Every puzzle requires that the player make choices, some of which lead to dead ends.
5. Puzzles
Puzzles in a game have a larger situation that gives the puzzle meaning. Applying the solution lets you move forward in the game.
5. Puzzles
Good puzzles have require insight. The insight above is to walk around the outside of the maze. Obscure insights, however, feel unfair.
6. Testing
Is it fun?
 How hard is it?
 Are there simpler solutions?
 Can it be improved?

The only way to find out whether a puzzle is fun is to watch someone play it. Often a puzzle you think is easy will turn out to be hard, or
vice versa. Sometimes players will find simpler solutions. Or you will realize that the puzzle needs some other improvement.
7. Sequence
Accelerating
Linear
Sawtooth
Semilinear
Ordered collection
Metapuzzle
Next you must put the levels into sequence. Linear is simplest, but can get tiring. A better organization is the sawtooth, which keeps going
back to easy puzzles, or to give players freedom to play puzzles out of order. Metapuzzles motivate players to complete the whole game.
7. Sequence: Transitions
Learning rules
 Within a puzzle: hints
 From one puzzle to next
 From one section to next
 Ending

You also need to think about the transitions between puzzles. Whenever the player moves from one place to another in your game, there is
an opportunity to lose the player’s interest. How can you bridge these gaps?
8. Presentation
Finally there are all the matters of presentation that turn an abstract puzzle into something people can see, hear and touch. I won’t go into
detail on production for puzzle games.
PROJECT
Inventing Ideas
Inventing ideas for puzzles
based on today’s headlines
The class divided up into teams of people each. Each team invented an idea for a puzzle game based on a
story or ad in today’s San Jose Mercury News. Finally the groups pitched their ideas to the whole class.
Scott Kim
Termite Control
 You
are a termite
 Goal: eat a floor
 Obstacle: humans
Like most of the puzzles this is a character-driven action game that has been turned into a puzzle game by putting it onto a grid and
turning real time action into turn based strategy.
Prison Shuffle
 Put
prisoners in cells
 Avoid bad combos
 Can shuffle cells
A dynamic allocation puzzle. Prisoners are arriving at a jail. Allocate them to cells while avoiding certain bad combinations, such as an
escape artist plus someone who has a key. Shuffling prisoners between cells takes time.
Cubicles
 Fit
cubicles in floor
 Leave path to doors
 Dilbert license?
A clever idea that falls naturally out of a real situation. Irregularly shaped cubicles made of square modules are to be fit within a floor of a
building. Additionally, every cubicle must have a clear path from its door to a building entrance.
Get Barbie Home
 Bust
Out Barbie
 Barbie Queue
 Ken’s Magnetic
Personality
A story about homeless Barbie inspired the most ideas. Get Barbie Home had Barbie wandering through the back streets of a city. Bust
Out Barbie required chain smoking Malibu Barbie use Fashion Barbie’s hairspray to fashion a homemade bomb and stage a jail break.
PROJECT
Rule Design
Turn Sokoban
into a word game
Next, groups were asked to invent a game that combined Sokoban with some sort of
word game, then pitch the game to the group. The ideas were surprisingly varied, and
several were sufficiently developed to be implementable.
Alexey Pajitnov
PROJECT
Level Design
Creating levels for a new
variation of Sokoban
As part of the Sokoban Word Game exercise, groups invented three levels of their games. Some of the levels were completely drawn out,
others were just titles or concepts.