If the object that is hit by Bullet is a Platform try with Gravity, first check the Direction of the Object with "Mirrored" if Bullet "Not Mirrored" and Object "Mirrored" move the Object with "apply force" to "Right" else to "Left" or with Gravity.X and Gravity.Y, note Gravity.X to move Horizontally and Gravity.Y to move it Vertically
If I have some time I'm going to make a .capx to teach you the process