We report an evaluation study for a novel learning platform, motivated by the growing need for methods to do assessment of serious game efficacy. The study was a laboratory experiment combining evaluation methods from the fields of learning assessment and psychophysiology. 15 participants used the TARGET game platform for 25 minutes, while the bio-signals electrocardiography, electrodermal activity and facial electromyography were recorded. Learning was scored using pre- and post-test question-based assessments Repeated-measures analysis with Generalised Estimating Equations was used to predict scores by tonic psychophysiological data. Results indicate some learning effect, plus a relationship between mental workload (indexed by electrocardiography) and learning. Notably, the game format itself influences the nature of this relationship. We conclude that a high quality of insight is afforded by the combination of subjective self-report and objective psychophysiology, satisfying two of three observable domains.