A very simple way to do it is with the bullet behavior.
If touch.x
is greater than character.x--> bullet blabla
is less than character.x--> bullet blabla
If you want to go to the background:
you can compare the distance form touch.x to your character.x, and set an apropiate bullet speed.
if touch.y (between xxx and xxx)
decrease gradually the size of the character.
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I think this could work fine.