How do I implement a damage system with knockback

Trying to get it so every attack raises a players damage when they are hit. The higher the damage the farther back and up the player will be pushed when hit.

You will need an instance variable that stores the damage (power) build-up and then whatever method you use to knock-back/up (8-way, pixel based, custom movement, bullet behavior, platform behavior, physics, etc, etc) you would use the damage (power) instance variable in the condition for various strengths...

Add the physics behavior and apply a one time force based on instance variable level with X,Y vectors should do the trick.

I'm using platform plus and physics seems to act a little funky with it.