Here a list of links from Academia, about game design and gamification
From game design elements to gamefulness defining gamification
From game design elements to gamefulness
Heuristic evaluation in game and gamification development
Methodological Review Of Playability Heuristics
(this article summarizes different heuristic to evaluate game usability, playability)
Other interesting resources
Heuristics and usability guidelines for the creation and evaluation of fun in video games (2002-federoff-)
(this is the first true study on video game usability)