Billy - Young man who is picked on by almost everyone in town, until he finds a powerful alien bazooka. Kathy - As you can guess, this is Billy's girlfriend. She loves her little toad. Both are zapped. Jeep and Ungar - Deputies that act like jerks.
Deputies always come in pairs, an imposing corn-fed one and another who is skinny.
These two fit that stereotype nicely. Blasted to donut heaven. Mr. Craig - Government agent, though we never find out if he has any inkling of his own purpose in this film. Investigating aliens is like that, you don't need any clear goals. Just a simple country doctor, not afraid to cut metallic growths out of his patients' chests either.