Yeah, I think that's unfortunate of how the jam works. As for the crazy visuals... there's a lot you can do with color theory; for example if the background is very chaotic but all very dark, or all with very low saturation, or all the same hue, or "blurred", and so on, you can make the foreground stand out from the background. Like if the voronoi background had colors ranging from 0% to 20% luminosity, and the foreground was mostly 80%-100% luminosity, it doesn't matter how chaotic the background is, it still has nice contrast with the foreground. The main problem was the intensity of the contrast within the background itself.
Now that you mention it, I think noticed during the stream there was a sync between the music and the background, which is a really cool touch. I thought it was more tempo-based sync than audio sync though. I think by the speed of the changes in background I meant more like the magnitude of the changes, like you're going form 0-100, when going from 0-1 would still be a noticeable and nice touch.