(at around 53 mins) When the Mom is driving the van, her sloppy lipstick appears and disappears a couple of times.
(at around 58 mins) When the beer waitress at the hockey game serves Darryl, Greg, and Richard, she only had 3 beers on her tray. When she turns to walk away she still has 1 beer left.
(at around 1h 30 mins) In the end scene when Darryl and Calvin are walking back into the house Darryl tells Calvin to be quiet so his wife won't hear, but she isn't home yet from going to get her father out of the mental hospital.
(at around 25 mins) The number of cookies on the plate next to Pops changes between shots from about four cookies to five or six.
(at around 1h) When Calvin gets beaten up at the hockey game he has bruises. The next day at the birthday party, they're gone.
(at around 53 mins) After Calvin runs over the police spike strip in the GTO, the tires on the car don't go flat.
(at around 58 mins) When the beer waitress thought Darryl slapped her ass and called her bad names she pours beer over him so he gets all wet. But in the next scene he is completely dry.
(at around 1 min) When Calvin is getting out of prison, he is casting a big shadow, but the two prison guards are not casting any.
The face of the grandfather clock inside the couple's house is painted on. It looks like the same time in each scene.
(at around 21 mins) On the cover of the DVD, Calvin's tattoo is on his forearm and says "United States Marine Corps". In the movie, the tattoo is on his upper arm and says "82nd Airbourne". On the back of the DVD there is no tattoo on the same forearm.
(at around 37 mins) When Pops points the shotgun at Calvin, the sound of a pump shotgun cocking can be heard, but he has a double barrel shotgun.
(at around 1h 5 mins) If you watch with CC/Subtitles. During the football game at the birthday party. A song plays. The caption will say "Dick Dale's Misirlou playing" but the song that's playing is "Pump It by The Black Eyed Peas". Although they both have the same samples but the song was Pump It.
(at around 1h 5 mins) When the fathers and sons are playing football in the backyard, and Tommy gets taken down, Nicholas comes up and you hear, "How do you like them apples?" but he is clearly saying something else.
(at around 1h 6 mins) As Greg is pulling Tommy up by the helmet during the football game, we hear a series of "ows" but when you see Tommy's face, his lips don't move.
Calvin wouldn't have to disguise himself as a baby if he didn't drop the diamond into Vanessa's purse. He could've just hid the diamond in his pocket.
(at around 21 mins) When Calvin is being examined, the doctor notes that the scar on his abdomen could be from an appendectomy. However, the scar is on Calvin's left side. Any doctor would know that the appendix is on the right side.
(at around 21 mins) When Calvin is being examined by the doctor, the tattoo on his arm reads "82nd Airbourne Division", this is mis-spelt and should read "Airborne"