If you hook onto a platform from below, then grab the ledge in the climbing state, you will be both pulling the platform up will pushing it down. For whatever reason the game prioritizes pulling up in this case so the platform will rise instead of fall.

Pressing Up+Down when near the base of a ladder and you will start climbing down through the floor.

When climbing a ledge that leads to an angled surface, after about a quarter of the way up if you press down to climb off, you will instantly be placed on top of whatever you were climbing.

TODO: provide images, translate some of the glitches at http://members.jcom.home.ne.jp/umihara/kawase3.html''