Mixed reality rehabilitation systems and games are demonstrating potential as innovative adjunctive therapies for health professionals in their treatment of various hand and upper limb motor impairments. Unilateral motor deficits of the arm, for example, are commonly experienced post stroke. Our TheraMem system provides an augmented reality game environment that contributes to this increasingly rich area of research. We present a prototype system which “fools the brain” by visually amplifying users' hand movements — small actual hand movements lead to perceived larger movements. We validate the usability of our system in an empirical study with forty-five non-clinical participants. In addition, we present early qualitative evidence for the utility of our approach and system for stroke recovery and motor rehabilitation. Future uses of the system are considered by way of conclusion.