Players can be invaluable in shaping a game. Olli Sotamaa categorized player uses into these categories: Designer’s Muse, designer’s Patient, Player as Designer’s Adviser, and Player as Designer. I will summarize what he said about using players for these different purposes. (Sotamaa, 2007)
Player as Designer’s Muse
Players can be used to gather ideas. Often a player will play a game in a way that was unintended by the designer. By knowing early on what these unintended playing styles might be one can add some design elements in for players who want to play the game in that manner.
Player as Designer’s Patient
In a doctor-patient relationship, players can play a game and designers can observe and diagnose any problems a player comes across in the game.
Player as Designer’s Adviser
Gathering feedback from players is perhaps the best ways to see your audience likes and dislikes.
Player as Designer
Allowing players to create their own content like levels or characters is a way to get diverse quality content for your game without the need to high extra programmers.