Sliced Animations :o

Hey everyone! just needed to pop a quick question, how would i create different angled death animations?

Here is my situation, the enemies in my games are simple round circles, however when the main character slashes through them, they will be cut in half in the direction that the main character went through them in, and a line will cut through in that direction following the main character.

cans someone explain to me how I could do this? thanks [:

Could be done in a number of different ways....Have you got a screenshot you could post?