The Crater Critter series changes are documented in Craig’s book. The gallery here includes some photos to expand on those distinctions.
As always Craig Halls’ book, Breakfast barons, Cereal critters and the Rosenhain & Lipmann Legacy, is my reference bible for cereal toys. This series is found on page 144.
For other cereal toy series and information refer back to the main section page, Australian Cereal Toy Premiums.