Hanging and moving UNDER a platform?

I've been trying to implement a feature whereby a platform character can "hang" under a platform (activated by holding UP while jumping) and then be able move left and right while hanging under the platform

(reference games : gunstar heroes, super contra etc)

Getting the character to jump and hang wasn't an issue after looking at the ledge climb examples.

However as there is no platform under the character, I cannot jump out of this state, nor can I get the character to follow the contours of angled platforms.

Any suggestions or guidance would be greatly appreciated.

You could change the animation, and invert the platform gravity.

Thanks, that might be worth a try.