In some versions, the scene in the theme song where the western man shoots a gun is changed to Scooby-Doo either running away or riding in an out of control car.
Original episodes ran 45 minutes (60 minutes including commercials). Syndicated versions were frequently shown as 30-minute two-parters.
Home video releases use an alternate opening and end credits sequence which removes references to licensed characters (such as The Addams Family, The Three Stooges, etc). Some home video releases omit the opening theme entirely.