― Reiner Knizia
This is one of my favorite game quotes, it encapsulates what designers need to keep in mind when thinking about what keeps a player engaged with a game long term. When playing a game, attempting to win that game will get a player to the end. Having a goal besides winning will bring the player back to the game again and again.
Players create goals in-game and out of game that affect players attitudes towards a game. They can be categorized in two major ways.
Game Created Goals
For example, in a dexterity games and sports, the players attempt to increase their skill in playing the game. By honing in on physical skills involved with playing the game, the players can keep a competitive edge over opponents and have a better chance of winning. At the same time the desire to overcome physical limitations and acquire new skills will keep players interested and returning to the game.
Mental challenges to the player is far more predominantly in board games. Puzzle elements in games need to walk a fine line between being challenging, and solvable. In an attempt to win players will learn to solve the puzzle faster. The design challenge is if the puzzle is too complex, no one will solve it, or want to, and if it’s too easy, then experienced players lose interest when the perceived difficulty is removed.
For games that create an engine of some sort, economic or otherwise, the players goal to win the game becomes optimizing the system. Designers challenge the player to find every way possible to make their engine as efficient as possible. Where the reward of efficiency is winning the game. Experienced players find continued challenges with the system through conflict with other players attempting to do the same thing.