Goofs

During Grandpa's first scene, his cigarette and beer swap hands briefly.

When Max is looking at the wine in the bait shop and goes to set it back in the box, he only sets it in half way. In the next shot it is all the way in, then back to half way in the next shot.

When grandpa sings the lullaby to Allie and she falls asleep, there's a close-up of her face with her hair messed up and covering her face. The next shot is a long shot and her hair is neatly drawn behind, as in a ponytail.

When Jack & Walter drive to the fishing spot , the exterior shots of the car show the Dodge Polara as a 4 door pillar-less hardtop, but in the interior scenes, it is a four door sedan, showing the B-pillar seen behind each man as they converse. As they speed back to the wedding, the four door sedan now appears in a couple of exterior shots, and now the hardtop is used during interior shots of both men through the windshield.

When Max and Maria are dining on the deck, they drink wine from a box. When the rain starts and they go inside, the box of wine disappears.

When the worm is escaping into the ground, the green wire pulling it along is clearly visible.

John finds his father dead on the couch, but Dad's head bobs slightly and his eyelids move.

When Max visits Maria as she is fishing, he pulls aside her boat which is sitting silently in the water. As they finish their chat, somehow Maria's engine magically starts running and she motors away. Kind of tricky for a "pull start" outboard to do without someone actually pulling the cord.

When the guinea pig is released in the restaurant and is running across the floor, it has a tail. Guinea pigs don't have tails. It is clearly a rat; it was thinner than a guinea pig. The rat is also solid gray as it was running across the floor but when Maria (Sophia Loren) picks up the animal, it is clearly a chubbier gray and white guinea pig.

In the scene where Catfish Hunter is hooked and pulling the boat through the water, the rear of the boat is up high enough to see that there is no lower unit (propeller) on the outboard motor.

During the dog chasing the cat scene, when they get outside, the dog overtakes the cat.

When Max and John are dueling with the fishing poles, the whole line where Walter Matthau says that the cat has been 'crapping on his paper for years' is dubbed. His mouth doesn't move.

When John and Max release the guinea pig into the restaurant, the health inspector starts to write Maria a citation for having a rat. She picks it up and recognizes what it is. She can't think of the name, but her mother does. This is unlikely, since her mother's English isn't nearly as good as Maria's.

In the first movie, Grandpa Gustafson says he's 94 years old. In this sequel, he says he just turned 95. So less than a year has passed but somehow Melanie's daughter Allie aged 3 or 4 years.

Max tells John that he just had his car seats "refinished". The correct word is "re-covered", or "re-upholstered".