SE320: Introduction to Computer
Games
Week 7: Core Mechanics
Gazihan Alankus
Outline
• Brief chat about projects
• Core mechanics
Outline
• Brief chat about projects
• Core mechanics
Brief Chat about Projects
• How is it going?
• Four weeks left for your first presentation
(December 13). What I expect:
– A simple but playable version of your game
– An in-class demo
– (Optional) User tests (what you learned, etc.)
• Meetings that you want me in
• Help session
Outline
• Brief chat about projects
• Core mechanics
Today’s Lecture is Different
• We will learn about elements of core
mechanics
• We will identify them in your game ideas
• I expect you to think and participate
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Rethink your game idea with these in mind
Chance
Keep these in mind while improving your game
[Jesse Schell, The Art of Game Design]
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Space
• Where things exist
– Discrete vs. continuous
– Dimensions (2D, 3D)
– Bounded areas, connected or not
– Nested spaces
Questions: Space
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Is the space discrete or continuous?
How many dimensions?
What are the boundaries?
Are there sub-spaces?
Are there multiple ways of modeling your
game’s space?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Objects, Attributes and States
Object
Attribute
Value
Attribute
Value
Attribute
Value
Example
Object
Ghost in
Pac-Man
Attribute
Value
Position
(100, 200)
Objective
Avoid
Pac-Man
Direction
left
Secrets?
(state machine)
Questions: Objects, Attributes and
States
• What are the objects in the game?
• What are their attributes?
• What are the possible states for each
attribute?
– How do attributes change state?
• Any secret attributes?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Actions
• What can players do?
– “Verbs” of game mechanics
• Operative actions
– Move a checker forwards
• Resultant actions (more strategic actions)
– Force the opponent to make an unwanted move
Actions: Emergent Gameplay
• Interesting resultant actions that emerge out
of users’ behaviors
– Identify them, nurture them
• Tips to support this
– Add more verbs
– Make verbs act on many objects
– Goals can be achieved more than one way
– Multiple avatars
– Actions that change constraints
Questions: Actions
• What are the actions?
– Which ones are operative?
– Which ones are resultant?
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What objects do they act on?
How many ways can players achieve their goals?
Can users change constraints?
What resultant actions do you want to see?
Are you happy with resultant/operative ratio?
What actions do players wish they could do?
– Can you enable them as operative or resultant?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Rules
• Tie together
– Space
– Objects
– Actions
– Consequences of actions
– Constraints on actions
Goals
• You can’t just tell them to do something unless
you set up the rules to favor it
Parlett’s Rule Analysis
Goals
• Concrete, understandable
• Achievable
• Rewarding
• Short-term
• Long-term
• Series of goals
Questions: Rules and Goals
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What are the foundational rules?
What are the related operational rules?
Are there different modes for rules?
What is the ultimate goal?
– Is it clear?
• Are different goals related to each other in a
meaningful way?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Skill
• Users’ levels of ability
• Categories
– Physical skills
• DDR, guitar hero
– Mental skills
• Puzzles
– Social skills
• Most multiplayer games
Skill
• Balance difficulty and skill for best experience
Questions: Skill
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What skills does my game require from user?
Are there categories of skill that I’m missing?
Which skills are dominant?
Are these skills creating the experience that I
want?
• Does the game demand the right level of skill?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
Chance
Chance
• Things happening randomly in the game
• Uncertainty -> Surprises -> Good!
• java.util.Random.nextDouble() may not be
enough
Uniform
Gaussian
Chance
Random
seed
Always different
values
Fixed seed
Same sequence of
values
Getting Chance Right is Tricky
• Calculate probabilities
• Make sure undesirable edge cases do not
happen
Risk Taking
• Expected probability vs. trust in own skill
• Example
– Monsters appear randomly
– What are the odds of me
killing a monster if one
would find me in that room?
• High? -> will risk going in
• Low? -> will not risk
Questions: Chance
• What in your game is truly random?
– What parts just feel random?
• Does randomness give
– Positive feelings (excitement and challenge)
– Negative feelings (hopelessness and lack of control)
• Would changing my probability distribution
curves improve my game?
• Do players have a chance to take interesting risks
in the game?
Core Mechanics
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Space
Objects, attributes and states
Actions
Rules and Goals
Skill
• Rethink your game idea with these in mind
Chance
• Ground your decisions with these
• Later in your presentations inform us how
they influenced your designs