Walking through the stronghold wall to get to the Old Castle campsite. Basically just wiggle up and down when on the left side of the gate to walk through the wall (clip from ver 1.2.3 on pc)

Jumping up the slope to skip the cable car ride. When you start walking up the path that goes up where you normally remove the debris from the cable car path, on the first major turn left, you can climb that slope by just jumping up it. Compared to some of the other jumpable slope surfaces, this one is pretty comfy and consistent (clip from ver 1.2.3 on pc)

How does the Switch super jump trick work? Has anyone tried that on PC?

Found a way to clip out of bounds and up-warp to the top of the Stronghold side of the canyon (tested on PC v1.2.3), and a way to jump from there to the other side of the canyon. Unfortunately, you can't just skip the second Grandma conversation, so you do need to backtrack there and talk to her before going back to the Stronghold side.

That being said, this means that a Low% run can now complete the game with zero items. Instead of repairing the bridge, you just perform the clip (again) to up-warp to the other side.

From what I can tell, the Switch launch just requires mashing jump after exiting to menu and then loading a save. It doesn't necessarily have to be a fast mash and I don't know how long you have to mash but the launch seems to be relatively consistent at least.