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.