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Tufts OpenCourseware
Author: Ming Y Chow

Tufts OpenCourseWare
Introduction to Game Development
M. Chow
Spring 2012


Game Design Principles

Motivation: Why Do We Love Pong?

  • Simple
  • Every game is unique
  • Elegant representation (of table tennis in real life)
  • Social: it takes two to play
  • Fun
  • Cool

What is a Game?

  • What are the differences between a movie and a game?
    • A movie does not require any input from a user; a game does
    • A movie has a predetermined ending; a game sometimes have no ending, sometimes have one ending, sometimes you can have multiple ways to die
    • You have to make (interesting) decisions. There are consequences for all decisions
  • What are the differences between a toy and a game?
    • Every game is unique; you face different choices in each game
    • A game has rules and clearly-defined goals
    • There may be constraints in a game
  • A game has a universe
    • Players
    • Objects (e.g., vehicles)
    • Terrains
    • Behaviors: e.g., physics, sound, speech, emotions
  • Pretending - the mental ability to establish a notion of reality

What is a Digital Game?

  • Immediate interactivity
  • Visible and measurable feedback
  • Narrow input and output
  • Information manipulation
  • Automation of complex systems (e.g., graphics, AI)
  • Network communications
  • Integration of all the traits above

What is Fun?

  • Games tap into human motivation systems
  • Fun = self determination theory

Game Design Principles

  • "Why should someone else play it?"
  • Identify the players and the audience
  • Identify the genre, which may automatically put in place constraints
  • Identify the universe and landscape
  • Identify the constraints and goals
    • Determine the criteria for success. How do you win? How do you lose?
  • Determine the rules of interaction
    • Controls; interaction with character, put the player in some environment
    • How do you explain constraints to the player? Do you tell a story?
  • Operational issues (e.g., delivery)


  • Semiotics - symbols; sometimes abstract and sometimes have parallels in the real world
  • Gameplay - the challenges that a player must face to arrive at the objective of the game; the actions that the player is permitted to take to address those challenges
  • Sequence of play - progression of activities
  • Goal(s) of the game - the objective of the game
  • Termination condition - a.k.a, victory conditions, a.k.a., end-game
  • Metarules - rules about the rules

Common Goals in Games

  • Beat the final boss
  • Save the princess
  • Capture the king, the country, flag, etc.
  • Save the world
  • Beat your opponent, the other guy
  • Get the highest score
  • Complete all the levels
  • Build the best {fill in the blanks} without going bankrupt
  • Sandboxing; play God (a.k.a., "wuss" mode)
  • Achieve something (e.g., reunite the Triforce)
  • Grab a lot of grub
  • Get the most kills
  • Kill everything that moves
  • Be the last man standing
  • Don't die
  • Beat the clock; don't run out of time
  • Character building
  • Build relationships
  • Solve a puzzle
  • Level up
  • Make the right choices (well, try not to screw up)

Designing the Gameplay: Making the Fun Happen

  • Some skill or strategy involved
  • Feeling of accomplishment
  • Immersion: you are living a different life, or something that you wish you were
  • Anticipation: do I look forward to playing this? Can this pass time? Sometimes addiction.
  • Replay value
  • A good story
  • Believable story
  • Good production
  • Real-world feel
  • Bug-free
  • At least give me a chance
  • Reasonable learning curve
  • Some variety
  • Not too linear
  • Game balance
  • Competition
  • Well, is it suitable for certain people?

Core Mechanics

  • Determines how the game actually operates
  • Consist of data and algorithms that precisely define the game's rules and internal operations
  • Should be so precisely stated that the programmers can write the code
  • Its functions:
    • Operate the internal economy of the game
    • Present active challenges
    • Accept player actions
    • Detect victory or loss
    • Operate the artificial intelligence
    • Switch the game from mode to mode
    • Transmit triggers to the storytelling engine

Designing Core Mechanics

  • Keep it simple and elegant
  • Look for patterns, then generalize
  • Don't strive for perfection (on paper)
  • Refinement is important

What are the rules and core mechanics of Monopoly?

Game Balance

  • Fairness (start symmetrical: equal resources and powers to all)
  • Asymmetrical
  • Challenges vs. success
  • Meaningful choices: low risk / low reward, high risk / high reward
  • Short vs. long
  • Rewards
  • Punishment


  • What happens when you win?
  • What if you lose?

Uh oh.....Game Design and Gameplay Blunders

  • Very flat; linear gameplay
  • Incorrect facts
  • Really really poor production: bad acting, bad voiceover, bad translation, bad everything
  • Bad physics
  • The unfinished or rushed game. The consequences:
    • Overworked developers
    • Bad testing; bugs galore
    • Doesn't sell well
    • Players get pissed
    • Patch /update hell
  • I need the CD to play this game?
  • False promise (a.k.a., Duke Nukem Forever)
    • Not as good as advertised
  • Dead as you know it
  • Unrealistic storyline
  • Bad camera control
  • Bad AI
  • Repetition, no variety
  • You can't save
  • I don't know what to do; lack of feedback
  • Really really clunky user interface
  • Too much emphasis on sound, graphics
  • Really bad sequel
  • Really bad support
  • Poor lighting
  • Bad port
  • Poor performance; game crashes

Game Genres

  • Classifications of digital game features
  • Describe the style of the game
  • Problems:
    • Most games fit into multiple genres
    • The list of nomenclatures goes on forever (see below)
    • No standard; been an issue of controversy
  • Importance: Set expectations
    • For players: they know what to expect in the game
    • For developers: they have to adhere to the design patterns (sometimes known as the "unwritten rules") of the genre

The Running List of Popular Genre Nomenclatures

  • Strategy
  • First-Person Shooter (FPS)
  • Real-Time Strategy (RTS)
  • RPG
  • Adventure
  • Action
  • Simulation
  • Sports
    • Racing
  • Shoot 'Em Ups / Beat 'Em Ups / Blow 'Em Ups
  • Brawlers
  • Fighting
  • Sidescroller
  • Puzzle
  • Party
  • God Games
  • Music
  • Space Shooter
  • 2D Space
  • Movie-Based / Full-Motion Video
  • History
  • Education / Edutainment
  • Simulation
  • Stealth
  • Interactive Fiction
  • Text
  • ...and this list goes on!

Genre: 2D Space (a.k.a., Shoot 'Em Ups; Arcade)

  • Examples: Space Invaders, Asteroids, R-Type, Defender, Chromium
  • Spurred the arcade boom in the '80s
  • Easy to develop
  • Problems: unrewarding; stale; not a good sell anymore

Genre: Simulation

  • Examples: SimCity, any EA sport game
  • Mimics real-world scenarios, including physics, atmosphere, and limitations

Genre: Massively Multiplayer Online Role Playing Games (MMORPGs)

  • Examples: World of Warcraft, Everquest, City of Heroes, City of Villians
  • Descendant of interactive fiction and Multi-User Dungeons (MUDs) (e.g., Ultima)
  • Popularly subscription-based for revenue stream
  • Character-building
  • Requires computer networking
  • Problems: software patches; out-of-game economies; addiction; can have lots of mundane and boring tasks

Genre: Interactive Fiction (a.k.a., Adventure, Text-Based or Graphical)

  • Examples: Blade Runner, the book, Adventure, Zork
  • Sometimes known as interactive drama
  • Immersive story
  • Primarily text
  • Completeness of world
  • Prose
  • Challenges and puzzles are typically conceptual solved by lateral thinking
  • The world is essentially a (mathematical graph) where each node in the graph is a separate scene
    • Tree
    • Death trap (many ways to be dead)
    • Open world
  • You are faced with discrete and limited choices
  • You could be dead as you know it, or loop around the world with no end
  • What to avoid
    • Puzzles solvable only by trial-and-error
    • Illogical spaces. Perfect example: Legend of Zelda (NES), the second quest
    • Require outside knowledge

Elements of a Game Design Document

  • Game Title
  • Overview
  • Gameplay mode
  • Core features in the game
  • Secondary features in the game
  • State diagrams (schematics)
  • Internal economy
  • Game balance
  • Victory conditions
  • Interface design (high-tech or low-tech)

The Importance of a Game Design Document

  • Memory (i.e., Have a plan? Write it down!)
  • Communications
  • Identify system limitations
  • Scope tentative project plan and budget
  • Good read: The 7 Deadly Sins of Startup Companies