Revealing mistakes: When Thornton and Lou are making the Bruce Springsteen sign, the student at the table is supposed to be writing on a poster but the marker is clearly not touching the paper.
Continuity: During the bar fight, Lou lifts up one of the fighters (who is wearing a red shirt and blue jacket). After he's thrown into the jukebox, he's wearing different clothing
Continuity: When the football team confronts Derek, Jason is standing more towards Lou near the booth. When the football player picks up Derek, Jason is now behind Derek. In the next shot when Thorton steps in, Jason is back near Lou.
Continuity: During the final dive sequence, Chas already has made one dive, but when he is about to make his second dive and gets cramps, his hair is perfectly dry and combed.
Continuity: The scenes at the college campus all have the trees in beautiful fall colors except the one in the diving scenes. These trees are all in a healthy summer green.
Revealing mistakes: When Jason is at the party before he goes outside and ends up hitting Chas, he is drinking beer from a bottle. When he exits the building, he is holding a can.
Revealing mistakes: When Thornton makes his first dive of the movie, he exits the pool on the ladder and there is clearly a cut in the film. He exits the pool dry, no water dripping anywhere.
Revealing mistakes: When Oingo Boingo performs at the party, the music is obviously the pre-recorded studio version of the song.
Continuity: When Chas and Valerie first show up at the caveman party, a girl in a pink outfit passes them and leaves the room. The scene then goes to a wide shot of the party, and the girl in pink is sitting on the couch. When it cuts back to Chas and Valerie, they walk into the room and past the couch, where there is no sign of the girl in pink.
Continuity: At the final dive meet Coach Turnbull is wearing a striped knit tie, while he is at the judges table explaining that Thornton is an eligible member of the dive team, the stripes on the knot of his tie change.
Incorrectly regarded as goofs: While there is a clear diving double for Rodney Dangerfield, there is too big of a difference to be accidental, it is clearly a joke.