Can we get low% added, possibly as a miscellaneous category?
I worked on it as a challenge and I think it's interesting
Here's a run:

Low% has a few major differences from Any%.

Low% does not collect the Level 1 Wind Ring, so to get speed up it must combine the Level 2 Wind Ring with the Level 1 Earth Ring, severely limiting the projectile options early on as compared to Any%.

Additionally, Low% does not collect the health upgrades in any stage, which makes health a more precious resource in the early game as compared to Any%. (Notably skipping the Stage 2 health up)

Finally, Low% skips the Level 3 Earth Ring, and therefore misses out on the "Blade" super-weapon. The Blade is normally used to dispose of the last 8 bosses very easily. Low% must come up with alternative strategies for these bosses.

I can add this as a Misc category. Also, seems fun to try it as a achievement alone.
Any difficulty requirement?

I did it on Normal, not sure what the best way to handle difficulty would be (we don't exactly have a lot of people running any% easy or hard, can't imagine we would have a lot of low% competition on different difficulties)

Here's a Normal-difficulty Low% run that doesn't play through the final stage over and over (19m50s total time):

Low% category created as a Misc. category.

Finally could watch the VOD. When I have some free time available, I'll try to finish the game with this ruleset and add some ideas to try to optimize it.

Awesome, thanks very much!