GameCareerguide writes: "Play testing video games is similar to focus testing other products. The basic goal of play testing is to improve the game by watching new users play it and recording data about what works and doesn't. Play testing is not the same as bug testing or functional testing, as its known in software development. If anything, it's closer to usability testing.
I was first introduced to play testing while working on David Douillet Judo, a mid-sized combat sports game developed at 10Tacle Studios Belgium, where I am a game designer. The development cycle was only one year, and play testing started six months before release. We planned to have about 200 testers for approximately 40 sessions".