Developers as Play Testers?

Lone wolf developers don't have the resources to do play-testing and market research like the pros. However, even the most "independent" game developer can take steps to ensure that the finished product is one that people are actually interested in playing. For starters, try to avoid letting the developers play test. The people making the game are not the best ones to play-test it.

It's perfectly OK for developers to test the game, but far too often developers acting as play-testers will assume the game is too easy, too boring, or too short. They'll more than likely want to spend time implementing "just one more feature" to make the game "perfect." This leads to the Infinite Alpha syndrome, explained above. To get an accurate measurement of how "fun" your game is, recruit game players.

Conclusion