I recently wrote a short introduction to Games User Research for PaulOlyslager.com.
The article covers topics including why user research is important to games, what are the differences between games and traditional UX research and some common techniques used in games user research.
It also includes some links to more information about games user research.
And a great article it is! I have been following your blog for a while now because user research in games was an unknown domain for me. A least ’till now! Cheers!