Well, one of the biggest changes was that Preacher the comic was on the road a lot as Jesse hunted God (and dealt with his family.) The show seems like it will be set in the small town. Cassidy wasn't being hunted by some Christian cult. Jesse had been kidnapped by his family and placed in his position as a preacher while Tulip thought he just up and left her. In the show, Jesse seems to have more free will in his decision to stay, and Tulip was well aware of where he was and isn't dealing with the anger of him leaving her. We aren't seeing any of the action going on in Heaven in the show.