When Jack is talking to Ty Webb while Ty is playing pool, four of the balls on the table disappear between shots.
When standing near the pool with Todd and Miffy, Kate puts a strawberry in her mouth with her right hand and at the same time hands Todd a strawberry with her left hand. In the closeup that follows, the strawberry in Kate's mouth has vanished and she is handing Todd a strawberry with her right hand.
Immediately after jack has hit the golf ball while using the aerodynamic golf trainer we see a golf ball being released by the machine and going onto the tee, however a second later in the next shot this ball has disappeared and another ball is released and goes onto the tee.
When Peter Blunt is on the phone, complaining that the power to Hartounian Enterprises has been cut off, he's using a cordless phone that wouldn't function in a power failure.
When the explosive golf ball is supposed to be blowing up the melon, no golf ball or anything else for that matter is seen hitting the melon before it blows up, it seems to just explode on its own.
When Jack Hartounian is getting ready in his bathroom for a date and drying his hair with a loud revolver shaped hair dryer, the dryer doesn't blow out air at all.
At 1hour 22 minutes several caddies are jogging down the course during the championship match. One of the caddys is wearing a black t-shirt that says "NIGHT RIDERS" but at this moment the letters are reversed on his shirt. Probably indicating a mirrored image.
The first time they play golf at Wacky Jack's country club the 18th hole is an ice hockey hole. At the end of the movie the 18th hole is different.