Within the field of Embodied Conversational Agents (ECAs), the simulation of emotions has been suggested as a means to enhance the believability of ECAs and also to effectively contribute to the goal of more intuitive human-computer interfaces. Although various emotion models have been proposed, results demonstrating the appropriateness of displaying particular emotions within ECA applications are scarce or even inconsistent. Worse, questionnaire methods often seem insufficient to evaluate the impact of emotions expressed by ECAs on users. Therefore we propose to analyze non-conscious physiological feedback (bio-signals) of users within a clearly arranged dynamic interaction scenario where various emotional reactions are likely to be evoked. In addition to its diagnostic purpose, physiological user Information is also analyzed online to trigger empathic reactions of the ECA during game play, thus increasing the level of social engagement. To evaluate the appropriateness of different types of affective and empathic feedback, we implemented a cards game called Skip-Bo, where the user plays against an expressive 3D humanoid agent called Max, which was designed at the University of Bielefeld  and is based on the emotion simulation system of . Work performed at the University of Tokyo and NII provided a real-time system for empathic (agent) feedback that allows one to derive user emotions from skin conductance and electromyography . The findings of our study indicate that within a competitive gaming scenario, the absence of negative agent emotions is conceived as stressinducing and irritating, and that the integration of empathie feedback supports the acceptance of Max as a co-equal humanoid opponent.