Explanation may include

• theory/psychology
• player engagement
• control (i.e., players make choices that affect the outcome)
• mechanics, balance, and rules
• rewards (e.g., scoring, advancement through levels, animations, random rewards)
• goals and feedback (i.e., games that provide clear, achievable goals and useful feedback)
• game loop/replay value
• effective marketing.

Process/Skill Questions:

• What criteria determine whether a game is successful?
• What role does the psychology of games play in a game?
• What is the difference between game design and game development? How do they overlap?
• How do challenge and reward interact to keep players engaged?
• How is the difficulty of the game balanced so the game is neither too easy nor frustrating?