Immersive Virtual Reality (VR) has been shown to work as a non-pharmacological analgesic by inducing [sic] cognitive distraction in acute pain patients. Researchers have shown that VR games have the potential to distract patients cognitively and function as a type of pain management therapy. In this paper, we introduce the gameplay and design metaphors of Mobius Floe (MF), an immersive VR pain distraction game for acute and chronic pain patients. MF introduces an experimental approach with more engaging game interactivity to improve cognitive distraction for pain relief. In MF, we designed game mechanics with specific pain metaphors and therapeutic elements in immersive VR. In this paper, we analyze and explain the overall gameplay design principles and each pain metaphor element implemented in the game. We believe the design procedures and the way we implemented pain metaphors will inspire game design ideas in VR health game design and provide potentially useful references for other researchers and game designers.