When Owen sits on the porch (with the door open), his mother sits in her chair in the living room, and Larry lies down on the rug between them. Momma sees Larry on TV and yells "There's a murderer in the house!" at which point the camera turns back to Owen, with Larry notably absent from his place on the rug. The camera then returns to Momma calling the police at which point another cut is made to Larry awakening, lying on the carpet again in his original spot.
In Larry's dream toward the end, Margaret drops a goblet from the balcony that consistently falls upright. Yet, it's upside down when Larry catches it.
When Owen smacks the teacup of soda out of Momma's hand it breaks on the door across the room, there is no liquid on the door or floor where the cup broke.
When Owen sneaks into Margaret's house, he's barefoot. Then when her gardener shows up and he hides behind the couch, it's obvious that he has shoes on.
When Beth kisses Larry on the kiddie train, her nose jumps from the left side of his to the right and back between shots.
The locomotive shown on the train is a switch engine. Switch engines are not used on road trains or Amtrak. Switch engines may be placed in the locomotive consist on road trains, however they are typically either isolated or dead-in-tow.
When watching "Oprah", Larry's TV is tuned to Channel 4. However, in Los Angeles, where this movie is set, "Oprah" actually aired on Channel 7, KABC-TV.
(reversed images) When Larry first follows Momma on the train she turns the corner and pushes the "push" sign to open the door. When she is shown coming through it, the push sign's letters are reversed. Next, just after Larry and Owen have pulled Momma back up on the train, Owen is hugging her. When Larry asks her if she is OK the push sign is on the left side of the door. Then Momma kicks him and the push sign is on the right with the letters reversed as he starts to lose his balance. Then they show Owen get up and say "Larry," after which Larry is shown falling off the train and the push sign has moved back to the left side with the letters correct again.
In the Cousin Paddy scene, Owen picks up a cast iron pan off the stove fresh from cooking eggs without protection for his hand. The handle of a cast iron pan is not insulated, so he would have burned his hand when he grabbed the handle.
When Larry reads out the title of a student's "coffee table book" he says "One Hundred Girls I'd Like To Pork" but his lips are clearly mouthing the word "Fuck." This line was presumably overdubbed to avoid an R rating. Worse yet, Pork was changed to Bonk for broadcast on commercial TV.
at around 1 min, somebody's hand is at the right in the frame.