Virtual reality (VR) is increasingly being used in serious game contexts. Virtual environments may include multi-sensory interactions that can overload cognitive processing and disrupt attention. Previous research indicates that cognitive load is affected by increased information processing in VR. However, the nuances of cognitive load are still unclear when distracted by different features of auditory and visual stimuli. Our goal was to establish a cognitive-motor dual-task paradigm in the context of a cup-stacking task for understanding how cognitive load is affected in VR by four distractor aspects: pitch, speed, amplitude, and proximity in visual and auditory distractors. We present the results of a within-subjects user study with 48 participants.