How about making the low% being the usage of the objects (crystals, bubbles, clouds, etc) Take track of all of them may be difficult, but they can be sub categories of lowCrystal% for example.

Even before learn anything about speedrun the game was a thing, I play most of the game using the least amount of objects for example in the chapter 1 you can completed only using 1. This in the last chapters becomes a nightmare if you try to avoid all of them, but only avoiding crystals or springs for example is viable (and also very fun to try)

What do you think about a lowCrystal% or lowSpring%?

And low% can be about the usage of objects, like crystals, bubbles, moving plattaforms, etc, this can be difficult to track, but for example low% of crystals could be a viable category