This was the first VR app prototype I worked on. It allowed you to listen to music while in VR, with the environment around you flashing and pulsating in rhythm to the music.
It never really worked properly because rapidly moving objects in VR tends to overwhelm your senses very quickly, and thus I had to drastically tone down the effects until they were almost negligible. This was a surprising limitation about VR -- close objects must remain relatively stationery. If they are pulsing and gyrating the human brain appears to get confused very quickly.
I developed this app using the VastDevKit, which I sort of developed in parallel.