Continuity: At the football game at the end of the movie, it starts to rain for a while and then it stops. Gigi is shown on the bleachers with wet hair and then a second later her hair dry and fluffy.
Revealing mistakes: When Jack catches the ball on the final play, the ref signals "touchdown" twice. Once when it catches it and again when he actually crosses the goal line.
Audio/visual unsynchronized: A few times during the movie when Reno yells at Jack, you can see Kurt Russell is saying "fuck" but his word is over-dubbed to the common fall-back words like "freak", "friggin", and "fool". Any use of the word "fuck" more than once would turn the film into an R-rated picture.