I like the music ! From your screen shots I think the bullets are supposed to change colors but I don't think that part was working correctly on my side.
I'd recommend to just leave the tab open and play other games without audio haha. The bullet colors and music only change when the timer reaches 0, which is about 4mins for the first one. I made the duration too long this time, will improve for the future! There's 5 tracks you can listen to.
