The Beatles song "I Want to Hold Your Hand" is audible over the noise at the stag party.
In the series, Lois is blond and wears a red shirt, Chris wears shorts and no shoes and has a deeper voice, Stewie wears a purple variation of his usual outfit as well as green overalls, and Meg wears a white shirt with blue lining. Also Quagmire's design in the pilot compared to what he looked like in the final version are displayed as two completely different characters.
Tom Tucker's name is Mike and his suit is very different in the pilot.
In "Death Has a Shadow", Peter says butter rum is his favorite ice cream, but in this, he says rum raisin is his favorite.
The priest at the church in a cutaway gag sounds very different in "Death Has a Shadow", and the line where Peter says "Woah, is this really the blood of Christ?", to which the priest replied "Yes," then Peter says "This guy must have been wasted 24 hours a day, eh?" is not in this episode.
In "Death Has a Shadow", the film Peter brings to the stag party is a porn-remake of Casablanca. But in this, it's just a regular porn video.
In "Death Has a Shadow", when Peter brings the pornographic film to the stag party he says "Did I bring the porno? You're gonna love it, it's a classic." But in the pilot he says "Did I bring the porno? Who am I? Some kind of porno-not-bringer?"
Even though it was pitched to a network, Peter's response of "Oh, that is bullshit!" to the Von Trapp family gag goes uncensored, where in "Death Has a Shadow" it is covered by applause.
The character who Peter plays "drink the beer" with is replaced by Quagmire in "Death Has a Shadow".