Revealing mistake: When they get back from Bunyans and the garbage is on the floor, Chet runs to the bathroom. The family and Roman follow him, you see Dan do a 3 count for everyone to run back In screaming, the blocking of that shot included a gap that you could see them off camera right.
Continuity mistake: During the bear in the cabin scene, after Chet puts the door back up, shortly after, you'll see the door is on the floor while Roman is fighting the bear with the oar from the steps. (Also, note in that same shot, you'll see the bookshelf was destroyed to pieces with its books all over the floor. That scene was never shown and must have been cut from the movie).
Visible crew/equipment: When the bear is jumping on the cabin door he busted down on top of John Candy you can see the bear trainer waving a stick in front of the camera to make him do his trick.
Continuity mistake: When Annette Benning is at the tops of the stairs with the twins while Dan Aykroyd is trying to fend off the bear, John Candy's younger son Ben is nowhere to be seen. In the next shot he is standing at the top of the stairs screaming with her and the girls.
Revealing mistake: When John Candy, Dan Aykroyd, and the two boys are fishing, you can tell they are on a studio lot, with a backdrop of a forest behind them. The reflection in the water from the "shoreline" is about 2 feet (at the most) away from their boat. If they were actually in the middle of a lake, the reflection wouldn't be that close, or for that matter, that clear. (01:00:09)
Continuity mistake: When the lodge owner rushes in with the shotgun/lamp to help with the bear, he plugs it in, the light comes on and the shade is in place, then John Candy takes the gun from him. In the next shot when you see him getting ready to shoot the bear from John Candy's view (looking door the barrel of the gun), the light bulb is out and the lamp shade is gone.
Plot hole: At the amusement park when Buck is looking for Cammie, it is lightly raining but no-one seems to be getting wet.
Continuity mistake: In the scene where John Candy is being attacked by the bear while under the door, from every long shot, the stunt double has the door's curtains over his shoulder and on his back, but in the close ups of John Candy himself, the curtains are over his shoulders and on his face.
Revealing mistake: When the family pulls into the lodge parking lot and they all open their doors into trees, the tree John Candy hits with his door wobbles noticeably in the overhead shot. From the regular view you can see it's a smallish size tree, but not small enough to move as much as it does, regardless of how hard he opened the door into it.
Continuity mistake: In the scene where Chet is packing up to leave after the skiing incident, and his wife Connie is attempting to talk him out of it, you can see her necklace, in various shots, under her shirt then out again several times.
Continuity mistake: When the bear is pawing at the windshield the first time, he's using his left paw, but in the next shot, it's the right paw.
Other mistake: When John Candy starts the drag boat, upon the sound of the engine starting, water starts flowing from the exhaust pipes but the engine never turns over.
Factual error: When John Candy throws alcohol on the fire after his bear story, there is a big explosion, but no amount of alcohol could cause an explosion big enough for a mushroom cloud, only gas or lighter fluid (especially the only small amount that is in John Candy's glass he's holding the glass is barely full and mostly ice.).
Continuity mistake: During the bat scene the painting on the mantel above the fireplace disappears and reappears, then disappears until the bat is killed.
Revealing mistake: When the bear gets shot in the hind quarters, you can see that the "bare skin" is nothing more than an overlaid prop based on how it shakes and moves independent of the bear as the bear runs away.
Continuity mistake: In the scene where John Candy is hugging his wife after dropping her dress to the floor, she appears to be wearing a full one piece slip. In the next shot she is wearing a half slip (waist down) and John Candy is un-hooking her string type bra.
Visible crew/equipment: During several shots of driving at the beginning of the film, the shadows of the camera and equipment can be seen on the hood and Candy's clothes. Its clear enough to see the camera, a boom mic, and a c-stand.
Continuity mistake: When Chet and Roman are talking at the beginning of the movie, Chet's Empire Strikes back glass turns from one shot to the next.
Continuity mistake: When Chet is pulling on the rope (thinking he's pulling up his nieces), the rope is over his left shoulder in long shots and his right in close up shots.
Continuity mistake: When Cara and Mara are at the cave and arguing about who gets to go first, the one without the flashlight goes in first, but when they're sliding down the cave, the one with the flashlight is first.
Answer: "Land of a Thousand Dances" performed by Wilson Pickett.