What is low% and is there a guide for it or a route?

In Low%, you're not allowed any powerups (or yoshi). The route is the same as Any%, except after you complete 5-1 you die to change the vines and then play 5-2.

i don't think there's a guide anywhere but i'd recommend watching a run to get the idea. it requires a shell jump in 1-3 which can be hard for people starting out which is partly why it doesn't get a ton of new runners

Curran Joseph has a shell jump alternative for beginners new to Low%, in case the shell jump is too hard:

Faster alternative to shelljump: Also the 5-1 death is pretty luck based and doesn't save much, so I would not recommend going for it until 26, my 27:21 doesn't do it.

Even if Juan lands in an inconvenient spot, you can go to the bottom to reverse his direction and then enter 5-2 while still saving a little over 3 seconds.

problem is that's also rng because it could just go up again

I've never experienced that before

EDIT: nvm just did

LOL rip

I guess if that happens you can just reset. If you don't want to risk resetting or losing all that time then yes go with Cad's advice