If Pepino is on a ladder going down when you restart a level (he doesn't have to be currently moving when you pause), you have control instantly when the level loads, possibly saving around 1.7 seconds IGT. I tested it on two ladders in John Gutter and two vines in Ancient Cheese. Below is a video demonstrating the difference between restarting a level with and without the ladder exploit.

that happens me once and i didn't know how it gets activated, now with this now i can say thank you for this, but i don't think if is worth it to used it

Does this save real time according to the category rules? I'm not sure if when Peppino spawns in is when you gain control or when the animation starts playing

According to the rules it seems like it would:

For normal levels: "Time starts on spawning into the level and ends on the up input on the exit"

The thing is, this exploit seems kind of annoying to set up, so it's probably best if either the rules are changed or if it's just disallowed. (Unfortunately, cause it's kind of cool)

Individual level run attempts should probably be kept in a vacuum. If you give yourself an advantage on a future run by doing something specific in a previous run, then you couldn't say the run REALLY start then, could you?

MAYBE if you started the timer from the moment you did a run to set up the glitch you could allow it, but that'd probably kill off any practical use for the glitch. Not to mention doing the setup at the start of every run is probably going to be a chore.

It might be best to simply disallow use of the glitch outright for single-level runs.