Other mistake: Sally is supposedly drying off a newly delivered puppy (looks like a yellow lab). Besides the fact that a vet wouldn't take a newborn from its mother unless there was something wrong, this puppy is dry, its eyes are open, and it looks about six weeks old.
Welcome to Mooseport (2004)
1 other mistake
Directed by: Donald Petrie
Starring: Gene Hackman, Marcia Gay Harden, Ray Romano, Maura Tierney
Continuity mistake: As we see Handy fixing the toilet in the President's house, he is holding a wrench in his right hand. Then after he bumps his head, he tries to get up and then grabs the wrench with his left hand. However, once the camera angle changes to show him getting up the wrench is back in his right hand.
Trivia: Monroe Cole states that people will be calling him Mr. President for the rest of his life. While it is true people do tend to call former presidents by that title (thus not a movie mistake), as a point of trivia; is it incorrect to address a former president as "Mr. President" or "former president (surname)." While Cole doesn't have to worry about his ex-wife taking his title, leaving office will do that. It's the media that perpetuates this presidential title error.
Question: Why did Gene Hackman quit acting after appearing in this movie?
Answer: As the other fine answers indicated, it was multiple reasons. An additional one was his health. Hackman said his doctor told him his heart wasn't healthy enough to withstand the stress and physical rigors involved in filming movies.
Moreover, Hackman didn't get along with the director, Donald Petrie, and stated that he hated this movie.
Answer: It was said, that he got tired of doing movies where everything and everyone explodes and dies a bloody death.
Answer: His decision to retire wasn't related to this film; it just happened to be his last. He was working on other projects (mostly writing), and wanted to focus on those. He didn't "officially" announce his retirement from acting until 2008.