Continuity mistake: When the security bar is placed on the guys sitting on the ferris wheel, the rifle appears on the back shots, but disappears on the front ones.
Continuity mistake: In the barn with Ward, who is covered in dust, Wood presses the gas pedal and Ward's head bends backwards for a brief second. In that angle, his head is spotless, only to return back to dusty in the following shots.
Continuity mistake: When Ward is about to nail the crown on the front door, his hand is facing right. A frame later it faces upwards.
Continuity mistake: When the Douglas' home is sliding down the cliff, it has moved a long distance seen from sea level view, but very short from Ward's POV.
Continuity mistake: After Ward enters the barn in reverse gear and comes to a stop, he is spotless, yet from a front shot, a frame later, he is covered in white dust.
Continuity mistake: When Ward turns the cannon and destroys the stuff in his home, the mess differs between shots, with stuff fixing itself and relocating somewhere else.
Continuity mistake: When the Douglas kids's bedroom plummets, the kid on the left is facing left, yet in the close-up he is facing the right.
Continuity mistake: After Kelso releases the sidecar's screw he makes a quick right turn, yet a frame later, from the wide angle, the handlebar and the bike are both facing straight.
Continuity mistake: When Kelso drives Sitarski in his sidecar, his white scarf swaps from over his chest to over his shoulder, back and forth.
Continuity mistake: When Kelso faints on the street a plastic Santa Claus falls on him, feet over Kelso's head. However, in the close-up, the Santa has turned 180º. Two seconds later, when the soldiers come to rescue him, Kelso and Santa have turned 45º to the right.
Continuity mistake: Kelso's plane has flames all around which suddenly disappear when the plane arrives downtown (and, most probably, different plane models and sets are used).
Continuity mistake: Kelso's plane crashes against a streetlight which hangs next to the cockpit, but it disappears in further shots.
Continuity mistake: When Kelso's plane crashes downtown the cockpit is covered in smoke, yet a frame later it's clear and opened with Kelso perfectly visible.
Continuity mistake: When Sitarski hands Betty the washed-up doughnut her hand is lowered resting on the bar. A frame later it's raised at chest level.
Continuity mistake: Sitarski is served one doughnut, grabs it and leaves an empty plate. A frame later, when the doughnut falls, a second one appears.
Continuity mistake: At the bar with Betty, Sitarski is offered a salad. The waitress' arms change positions between the wide and close-up shot.
Continuity mistake: While Wally watches the dance club from the window outside, a dog sitting on its hind legs by the edge of the curb, swaps to standing on all four legs by the middle of the curb.
Continuity mistake: When Kelso's plane leaves, the loose petrol hose's position and movement differs between the wide and close-up shots.
Continuity mistake: After Wally picks up the picture in the sink, the amount of foam on the skimmer decreases between frames.
Deliberate mistake: A piece of food lands on a soldier's soap and splashes on him. When the angle rises his glasses are covered in soup. The lenses are very obviously painted, for the splash was way to small to produce such mess.
