Well, you have Frankenstein's obsession with body parts and Igor's back.
More use of electricity. I really like the 'He's ALIVE' one though. Describes me when I have to wake up for school.
Here, you can see that Watterson refrained from calling the monster 'Frankenstein' but makes the scientist out to be really evil instead of just obsessive and blinded.
See the little jumper cables and the lightening in the background? More electricity and more Igor. Plus, the crazed look in Frankenstein/Garfield's eyes and the demented look of Igor/Odie. Kawaii! ^_^