This is more of a curiosity question than something I'm imminently working on, so no urgency on anyone's part required. Though if someone has come up with something ingeneous, I'd love to hear it.
Many arcade "platformers", especially of the nineties, have a particular quality in their platforms: You can "jump up" to a higher platform (usually by pressing jump + up) if you can reach it, or "jump down" to a lower one (jump + down) if you aren't on the lowest level. But at the same time, you can jump or duck without traversing between platforms (jump without up, or down without jump), usually to avoid enemies or their projectiles.
It would by easy enough to make all your platforms into ladders, but doing so could (I think) both interfere with jumping (getting tangled in a ladder, provoking a climb animation, and so on) and with ducking (pressing down will move the character on the "ladder" down rather than ducking).
Has anyone devised a simple way to achieve this effect?
Arcade games that come to mind that use such effect include "Rolling Thunder", "Willow", and "Twin Wonders", among others.