Continuity mistake: When Jason writes the paper and then staples it, there are neat/short bits of paper at the side edge, where the pages were torn from the notebook (also visible after he slams into Marty's limo). Then, when Marty finds the paper, the entire left side edges are filled with much longer extra bits of paper. (00:06:50 - 00:09:55)
Continuity mistake: Just after Jason's parents leave, when Rudy pulls up to pick up Janie the front passenger window is rolled up, but when Janie and Rudy turn to head back to his ZR-2 and he says, "Peace out, little G," that window is rolled down. (00:15:10)
Continuity mistake: When Jason leaves Marty's limo he exits from the left side of the limo, on the driver's side. In the next exterior shot, he is leaving from the right side of the limo, the passenger side, which is the side Marty sits on. (00:15:47)
Continuity mistake: Jason and Kaylee arrive in LA on Thursday, and phase one begins Friday morning, but during 'phase one: surveillance day', when Jason and Kaylee are at the stunt demo, Jason looks at Marty's iPAQ PDA and the date reads Sunday, June 4th (stunt demo noted between 12:30 and 1:30pm). Yet, when Vince, the stunt coordinator, tells Marty that he's taking the next day off (day of 'phase two') to take his granddaughter to a birthday party, the clown invitation notes July 28th as the day of the party. Then, on Saturday 'phase two: the take down', when Jason is seated at the bus stop he looks at Marty's PDA and the date reads June 22nd, the day of the 'Whitaker and Fowl' premiere and party. Go figure... (00:35:50 - 00:52:40)
Continuity mistake: The morning of 'phase two: the take down', when Marty awakens at 6:45, in the close-up he lifts the snug ice-pack mask to his forehead, but in the next wideshot the mask has vanished though he hasn't touched it. (00:39:40)
Continuity mistake: During Marty's drive to the bogus address, when he is done speaking with Monty, just as he says, "Wolf out!" he pulls the phone wire and the earpiece actually pops out of his ear, but in all of the following shots that earpiece is still in his ear. Since the super-glued earpiece is one of the main plot points, this is bizarre to say the least. (00:44:25)
Continuity mistake: When Marty is done speaking to Monty while driving to the bogus address, after he pulls on the phone wire, in the shot from his car's interior we can see that the wire actually ripped, but after nearly colliding with "grandma" the phone wire is again intact. (00:44:30)
Continuity mistake: Just after blue-Marty ends the call with Monty, in the shot facing Marty's car from the POV of the old woman's car just as Marty swerves to avoid her, Marty's window is rolled down, but in previous and following close-ups that window is rolled up. (00:44:30)
Continuity mistake: Before and after Marty's appearance at the birthday party, his car's five-point star hubcaps are visible in close-ups. After Marty's encounter with Masher, when the car is towed its hubcaps are entirely different. (00:44:50 - 00:50:25)
Continuity mistake: When Marty enters the home of the birthday party, there is a large area rug lying directly in front of the set of double French doors. In following shots, this large rug has moved closer to the front door (before all the kids jump on him) - note the table beside the French doors. (00:45:00)
Visible crew/equipment: At the bogus address, when Marty opens the doors to Aaron's birthday party, after Aaron shouts, "Let's hurt him," and rushes towards the "clown", in the next shot of Marty the blue stunt mat is visible on the floor, behind him. (00:46:00)
Continuity mistake: After Marty leaves the birthday party and asks Monty to reschedule with Marcus Duncan, when his car's radio starts blaring Marty's wearing his seatbelt in the shot facing him, but in the next side shot as he tries to turn off the radio Marty's seatbelt is instantly off. (00:47:35)
Visible crew/equipment: In the first step of phase four, after Frank's limo has "stalled", when Jaleel drives off with Marty who shouts, "Sayonara, loser," in the next shot and two shots later the reflections of a crewmember (wearing shorts) running backwards, other crewmembers, the boom mic, camera and equipment are all visible on the limo's surface. (01:05:30)
Continuity mistake: During phase four, when Marty opens the passenger door of Jaleel's speeding car he wears a baseball cap, but in the next wideshot his head is bare as he hits the ground and rolls - the baseball cap is gone, it didn't fall off. After a close-up of Jaleel, it cuts back to Marty and the baseball cap is back on his head just before it falls off, as he continues to roll. (01:06:40)
Continuity mistake: When Marty is up on the roof with Jason after being busted as a liar, he looks down at Marcus Duncan standing in front of eight live feed monitors, but in Duncan's close-up there are fourteen monitors. The entire top row of monitors is gone in the wideshots. (01:17:55)
Revealing mistake: You can tell when Jason jumps from the building while Marty is chasing him that it's a stunt double. If you look carefully at the face, it's obvious that it's a different person. (01:19:30)
Continuity mistake: In the scene where Jason's parents arrive at the airport in Los Angeles his mother is wearing a brown jacket. It remains brown until the scene where Jason meets his parents at the set and his mother's jacket is maroon. While she has more than enough offscreen time to change jackets, she does not have a jacket to change into (they are driven straight there) and no reason to change the jacket.
Other mistake: When Marty Wolf gets out of his pool, his shorts aren't dyed blue. If that one little bottle of light blue dye was enough to dye Marty Wolf's skin, it certainly would have dyed his shorts.
Visible crew/equipment: After Frank's limo "stalls" during the first step of phase four, when Frank tries to hug Marty just before Jaleel shows up, in the shot facing the back of the limo the reflection of the boom mic (with its fuzzy wind cover) is visible on the limo's surface.
Plot hole: When Marty Wolf comes out of the pool he is blue from head to toe yet with all the swinging of his hands and dancing, let alone the mirrors in the hall, he does not notice he is blue until he has put orange dye in his hair. How could he miss it?
