Are you manually parenting planes with a shadow texture under gameobjects? Tweaking, rotating, and maintaing a separate texture atlas just for shadows?
That process can be tedious, and even more so as you increase objects in the scene.
Easy 2d Shadows provides the best method for adding 2d shadows. Simply attach the script to a 2d sprite, and apply your desired shear/scale amount for a realistic look. Works best with 2d Toolkit . You have the option to tick the animated setting for sprites that are constantly changing their UV.
*Doesn't require separate atlases.
*Works on animated sprites.
*Clones the sprite at runtime, no need to update shadows when you change your objects.