Music audio concepts and design for VR are relatively under-explored compared to visual analogs. This paper ad- dresses the design and evaluation of a dynamic experience of music in Web VR called VRTGO, in which a user explores three alternative versions of the same song called “VTGO (Vertigo)”. Each song version is represented visually by a spiral of blocks emanating from separately located vortices on the ground. The closer the avatar is to one of the three- block spirals, the closer the audio experience is to one of the three intended versions of the song, in terms of tempo and instrumental mix. We describe the use of granular synthesis to achieve smooth tempo transitions, and present findings from a user study exploring engagement and enjoyment. The study finds that participants spend significantly longer in the dynamic version of the experience and report significantly greater engagement, though no significant differences in en- joyment are found between the dynamic and static versions. While users’ stated benefits of VR music experiences include enhanced creativity and emotional engagement, drawbacks such as accessibility and over-immersion risks are identified. The technical contributions and results of this work could be of interest to music artists and producers looking to explore the possibilities associated with rendering their creations in VR, and how these experiences enable novel ways to engage and interact with their audience.