One of the trump cards of digital educational games is their enormous intrinsic motivational potential. Although learning game design is often understood on a one-fitsall level, the actual motivational strength of an educational game strongly depends on the individual learners, their very specific goals, preferences, abilities, strength and weakness, personality, and experiences with gaming. Considering motivation being a fragile and constantly changing state, it is important to continuously assess learning and gaming processes and the oscillations of motivation and immersion within a game. With this premise in mind, the authors developed a psycho-pedagogical approach to a noninvasive embedded assessment of motivational states and learning progress, feeding into a dynamic, ontology-driven learner (and gamer) model. To evaluate the approach, the demonstrator games were subject to intensive quantitative and qualitative experimental research. Results show that a meaningful personalization and an individual support are key factors of the success of learning games.