When Mark Hamill makes his entrance at the convention, he uses his lightsaber to knock down several cardboard cutouts of Imperial Stormtroopers and one of Wonder Woman. Hamill, at the time, did the voice of The Joker, in the DC Animated Universe series.
Earlier in the episode, specifically during the convention advert, C-3PO also ended up fighting (and losing) against a Cylon in a tag-team wrestling match, with R2-D2 refusing to help. The advert also had him alongside R2 being referred to as the "gay robots of Star Wars."
Homer's sleeper hold looks more like a Vulcan nerve pinch from "Star Trek".
Mark Hamill hollers at Homer to "Use the forks!" to foil Louie's assassination attempt on Mayor Quimby, a parody of "Use the Force", one of the catchphrases from the "Star Wars" film series.
When Fat Tony says, "I am not so much disappointed as I am blinded with rage", the dark circles under his eyes disappear.
When Quimby falls out of the window from the view looking at the building, the window for the floor below is visible, but when the camera angle changes to behind Homer's head the window is gone and only a solid brick wall can be seen all the way to the ground.
In the final scene, when Homer is carrying Mark Hamill, you can see a person on the ground, whom Homer kicked. However, a person walks in front of him, and when he passes, the person is not there anymore.
Additionally, throughout that final scene, several bystanders' outfits and hair change color.