I would like to see these options:
Hide UI in fullscreen - pretty self explanatory, don't show the top UI when in fullscreen mode.
Hotkeys for adjusting glow value and rotation speed so these parameters can be controlled in fullscreen without needing the UI.
Export to PNG sequence - self explanatory, export the loop as a sequence of PNGs.
Built-in export to MP4 - although I would much prefer PNG sequence.
Adjust number of reflections - self explanatory