As the size of software program code bases in software development projects increases, insight into and comprehension of their underlying dependency structures presents a challenge for programmers. The increasing availability of virtual reality (VR) systems brings VR-based visualization of program code structures into practical reach for software developers and could support program comprehension and insight. However, the complete visual immersion with VR presents a cognitive burden and potential distractions. Applying gamification to such a VR visualization capability has hitherto been insufficiently investigated as to its potential motivation and program comprehension factors. This paper describes and evaluates a VR digital gamification approach for program code called VR Gamified Immersion in Software structures (VR-GaImS), which applies digital gamification to a multi-metaphor VR visualization of software program structures. The results of a preliminary empirical investigation utilizing our prototype indicate its potential to increase enjoyment and motivation, focus attention, and encourage the exploration of software structures.