Elements of a Successful Game

According to Raph Koster in his book A Theory of Fun for Game Design, a successful game has six successful elements: Practicing in advance, gearing up for battle, building a poker hand                 ​Landscape, board, relationships between players Interesting ruleset, movement, recurring puzzle Content; enemies, environmental obstacles Variety; multiple tools, special moves                Not based on luck; based on timing, dexterity, etc.
 * Preparation 
 * A Sense of Space 
 * A Solid Core Mechanic
 * A Range of Challenges
 * A Range of Abilities Required to Solve
 * Skill Required to Use These Abilities 

In addition, three other features are required to make it a good learning experience:
 * A Variable Feedback System
 * ​The outcome of any encounter should not be completely predictable​
 * The Mastery Problem must be dealt with
 * ​High level players cannot get too much out of easy encounters
 * Failure Must Have a Cost
 * ​There must be at least an opportunity cost, otherwise preparation would mean nothing