Presentation at seminar for the Institute for Management Research of the Radboud University Nijmegen. The development of serious games is becoming an ever increasing part of the game industries. Following the success of entertainment games concepts of motivation, and the psychology behind human behavior and behavior change are being implemented in serious games. The design of a serious game, or edutainment environment, is a challenge that, to all good intentions, often results in a direct a direct translation from offline media, or training regimes to an on-line digital medium. Developing motivating 'serious' games is not a straightforward development process. In fact, without suggesting that games cannot be developed for serious purposes, several have claimed that a game should not be considered serious at all. From a player's perspective there is certainly a big difference between playing a game because they enjoy it, or whether they feel they need to. The development of a serious game is an effort that requires a combination of goal-oriented design, coordination between specialist in multiple domains and a good relation and open communication to the target group. In this talk I will present data and discuss the importance of measuring user states, design for adaptivity and the development of health games.