With the increasing potential for gaming hardware and peripherals to support biometrics, their application within the games industry for software and design should be considered. This paper assesses the ability to use a form of biometric measurement, heart rate, in real-time to improve the challenge and enjoyment of a game by catering it to individuals of varying ability. While the findings of this study are valuable to game developers interested in providing additional dimensions to gameplay and testing, they may also be useful for those researching medical or therapeutic applications for games. The results suggest that although the tested game was inherently challenging and enjoyable, the adaptive affective gameplay was not altering the game enough to induce strong physiological or emotional responses from participants. Biofeedback games lend themselves to medical applications, but adaptive affective games can be used to respond sympathetically to the player without requiring direct control of physiological responses as a form of input.