I did a few Blobby Science related tests this afternoon and recorded a video that I may upload at some point in the future. I learned two things:

1. Health recovers from Candy Floss, not from score. You know how you get a little YAY when you complete a gate? Well you get that little YAY sometimes outside of a gate, and you gain back some health, and I thought for the longest time it was tied to score. Confirmed it is not - did not get one outside-gate YAY in my first run with 15k score. Got multiple outside-gate YAYs when in the next run before even hitting 5K score, by focussing on Candy Floss.
2. The bonus level (that we take a death to not activate), appears to not be score related. I tried playing the level conservatively, scoring as little as possible and still had 15K at the end - but because I hadn't died, I got the bonus level. I would like to try and complete the level with even less score if possible to test this some more.

sorry i didn't see this until now! but genuinely it's so funny to me that we're now having forum discussions about this silly game lmao

yeah a while ago i tried to figure out health recovery, it kind of looked as though it recovered every 7500 points but this wasn't consistent at all so i gave up on that theory and couldn't come up with a new one.

in one of the booklet things it says bonus levels are tied to secret missions such as colouring the whole level (too time consuming for any% and that's the only example listed unfortunately), and that collecting every item in a bonus level lets you skip 1 level so definitely something to practice for a blobby% run but not super helpful here.

(in other news, i finally added your latest run to my spreadsheet (yes i have serious issues) and the new best hypothetical time is 7:05.953.)