Interactivity & the Core Game Mechanic

1. Interactivity & the Core Game Mechanic • Foundations of Interactive Game Design • Prof. Jim Whitehead • February 6, 2008

2. Today’s Assignment • Work Breakdown and Schedule • Due Today • Have exams and game concept documents • Come up on stage after class to retrieve

3. Upcoming Assignments • Busy week next week • Partially Operational Game Prototype • Due Friday, February 15 • Need to have started your game • Need to have at least some things working already • Demonstration that you have spent at least 5-10 hours on your game already • Progress Report • Also due Friday, February 15 • An update on where things stand in your schedule • Is your project completing tasks on schedule, or falling behind?

4. Game Design Workshops • Game Maker • Wednesdays, 6-8pm • Engineering 2, room 180 (Simularium) • Enter on plaza level between E2 and JBE • RPG Maker • Wednesdays, 5-7:15pm • Engineering 2, room 280 • 2nd floor, on front of building, on driving circle/Communications end (right side, east end) of the building • Arrive by 6pm to avoid external doors locking • Knock on nearest door if late… • CS 20/C# and XNA Game Studio Express • Thursdays, 4:30-7pm • Engineering 2, room 399 (third floor, by elevators)

5. Interactivity • What was the essential element of computer games that made them so compelling, and allowed the industry to grow so quickly? • Not video, audio, or text by itself, since these all predated video games by many years • Interactivity! • Computing power makes this interactivity possible. • “Just as the schwerpunkt of computers is processing, so too the schwerpunkt of all software is interactivity—and this goes double for games.” • “Graphics, animation, sound, and music are all necessary to gaming, and they’re all important, but they’re not the schwerpunkt. Interactivity (sometimes called “gameplay”) is the real schwerpunkt of games.” • Chris Crawford on Game Design, p. 74. • Schwerpunkt: focal point, or, concentration of effort point, or, central point of attack

6. Definition of Interactivity • Crawford uses a conversational metaphor • Interactivity is, “a cyclic process in which two active agents alternately (and metaphorically) listen, think, and speak.” (p. 76) • In computer games, the computer takes the role of one agent, and hence interactivity for video games becomes: • “How can we program the computer to be an entertaining conversational (metaphorically speaking) partner?” (p. 77) • Computer must • Listen well • Give the player the opportunity to say anything relevant to the situation • Must think well • Must speak well

7. Interactivity Feedback Loop • Can view a computer game as a kind of control system • Game creates output • Player reacts to this output by making decisions and taking action • This generates one or more inputs • Game reacts to these inputs, creating more outputs player makes internal decision game creates output player takes action Rules of Play, p. 316

8. High Interactivity • What is high and low interactivity in a game? • Is a fast-paced action game more interactive than a complex, slow-moving strategy game? • Not necessarily. If two people talk quickly, does that make their conversation more interactive? • High interactivity comes when both sides are engaged in high-quality listening, high-quality thinking, high-quality speaking.

9. Assessing Interactivity in a Game • Crawford states that you can estimate the interactivity level of any game by asking three questions: • How much of what the player might desire to say does the game permit the player to actually say? • How well does the game think about the player’s inputs? • How well does the game express its reactions?

10. Applying the Questions • Fast-paced action game: • Game allows player to say a limited number of words (move up, down, left, right, fire, etc.) • Player can say these words quickly • Processing is simplistic: just move around on a map • Expressiveness is complete, within the very limited confines of the world. • Conclusion: small amount of interaction

11. Applying the Questions (2) • Civilization • Pace is slower, but player has wide range of things they can express • Game executes complex set of algorithms. • Listening and thinking are much deeper in this game • Expressiveness is also quite high – many possible pieces to move, possible interactions among pieces • Conclusion: Civilization is clearly a very interactive game • OK, so are real time strategy games like Age of Empires or Empire Earth more interactive than Civilization?

12. Graphic Realism • Crawford lists as a common mistake, “obsession with cosmetics” (p. 107) • Five common motivations for putting good graphics and sound in a game: • To further the gameplay • To permit the player to show off the superior cosmetic capabilities of his new computer • To show off the superior technical prowess of the programmer • To keep up with the competition • To provide the player with images and sounds that are intrinsically pleasing • Crawford: The first reason is the only good reason for pursuing cosmetics. • Agree or disagree?

13. Process Intensity vs Data Intensity • Process intensity is the degree to which a program emphasizes processes instead of data. • Process is algorithms, equations, branches • Data is reflected in data tables, images, sounds, text • Analogies • Language: nouns vs verbs • Economics: goods vs services • Computers: bits and cycles

14. Crunch per Bit Ratio • “Because process intensity is so close to the essence of ‘computeriness,’ it provides us with a useful criterion for evaluating the value of any piece of software. That criterion is a vague quantification of the desirability of process intensity. It uses the ratio of operations per datum, which I call the crunch per bit ratio.”(Chris Crawford on Game Design, p. 89)

15. Core Game Mechanic • To have interactivity, must have interaction from player • The player performs some action or actions.... • ... that intervene in the game world. • Usually, one or more of these actions occurs very frequently, and is the dominant activity of the player • This is the game’s core mechanic • Core Game Mechanic • The essential play activity players perform over an over again • Rules of Play, p. 316. • When designing a game, an important question to resolve is:What does the player do? • Your design is in trouble until you can crisply answer this question • ...and the answer sounds like fun

16. Examples of Core Game Mechanic • Breakout • Player turns knob on controller (or move lever of joystick) to move paddle left and right • Choose where ball hits on paddle to control movement of ball

17. Examples of Core Game Mechanic (2) • Most platformer games • Player moves left and right, and jumps • Avoid moving enemies • Core game mechanic isn’t all of the kinds of interactions a player may have with a game • More focused: only the most frequent and important interactions • In Kirby’s Adventure (NES), in additionto the typical moving and jumping,the core mechanic includes inhaling

18. Examples of Core Game Mechanics • For most shmups, core game mechanic is: • Move to avoid enemies and position ship • Firing at enemies • Collecting powerups • Different games can alter this. • In Radiant Silvergun, part of the core mechanic is selectingwhich weapon to use Perfect Cherry Blossom

19. Core Mechanic Discussion • What is the core game mechanic in the following games? • Guitar Hero II • Mass Effect • Halo 2/3 • Ratchet & Clank: Future