Defeating Monsters feel

So for this game I purchased it as a template from the Unity Asset store. I replaced the animations, and the models with my own. Also to put my own unique twist on it. I added monsters in the video game which you have to defeat at the same time you are playing the tennis match. The minion is a little dwarf with a machine gun that uses ray casting in unity to detect which direction the gun is pointing at. Once the ray collides with the German Sheperd and the user presses the left mouse button then the wolf takes damage. Also the user can swipe the direction he wants to hit the tennis ball in.