Continuity mistake: On the airplane, the shark bites off April's hand at about the wrist area, but when Fin pulls the gun in April's hand out of the dead shark, the severed limb is an entire arm up to the elbow.
Other mistake: While Fin and the others are on the subway, it keeps cutting to show about 15 people waiting on the platform at Grand Central, and nearly every one of those extras are also seen as passengers aboard the 7 with Fin, in different subway cars.
Visible crew/equipment: While Fin's on the Empire State Building's observation deck Skye's holding the freon connection together, and after Fin picks up the chainsaw and cable just as he shouts, "Ready?" we can see the reflection of set lighting on the glass door.
Factual error: When they're all on the 7 it makes an emergency stop at the 96 Street station, but that's impossible since that line only travels cross town along 42 Street, it doesn't go uptown to 96th.
Continuity mistake: When the 7 train comes to an emergency stop, the tiled wall beside the tracks read Grand Central, but on the platform the pillars read 96 Street.
Other mistake: After the explosion at the top of the Empire State Building, when Fin's soaring through the air he grabs hold of the chainsaw and powers it up to use on the sharks, but in one shot the cutting chain has been removed from the chainsaw's guide bar. Then the cutting chain is back, but it's not moving even though we hear it working.
Visible crew/equipment: After Fin and the others have collected weapons, they all get back into the cab waiting for them on Broadway, and when the cab starts to drive off we can see the reflection of the camera on the back passenger window.
Continuity mistake: After Fin and the others exit the subway there's a baby shark stuck onto Fin's denim jacket which results in a large tear in the material, but that large tear in Fin's jacket vanishes and instead shows just a few small marks thereafter.
Visible crew/equipment: On the Empire State Building's observation deck, after the freon connection has come loose Skye goes to reconnect it, and just as Fin shouts, "Got it?" on the glass door we can see the reflections of two crew members and the camera. (01:18:50)
Visible crew/equipment: Just as Fin and Skye reach the hotel's roof and open the glass door to step outside, the reflections of two crew members are visible on the glass door.
Other mistake: When Fin is standing atop the fire engine slicing into the overhead shark, the chainsaw's cutting chain has been removed from the guide bar - so it couldn't actually slice, but then the cutting chain is back in place.
Visible crew/equipment: While Fin's on the Empire State Building's observation deck Skye heads down to make a freon connection, and right after the closeup of the shark in the sky heading for the building, when it cuts to Fin we can see the reflections of the camera, two crew members, and a red step ladder with a yellow top (possibly a Werner ladder), all reflected on the glass door. (01:16:50)
Continuity mistake: At the start, Fin and April are seated over the aircraft's wing and the cockpit is located ahead of them on the same deck, but in the exterior shots of the aircraft the flight deck's location is on the upper level.
Continuity mistake: While on the 7 train, when Fin looks out the last car's window and sees the flooding and oncoming sharks, as he shouts, "We're in trouble!" in the closeup we see the door has certain stickers and markings and there's an advertising poster on the wall, but when it cuts to the wide shot it's all changed.
Continuity mistake: When April's lying on the gurney, just as she's wheeled through the doorway it cuts to the closeup as the nurse turns to block Fin from entering the ER, and behind the nurse we see the gurney still being turned and wheeled into the room, but April has vanished.
Other mistake: The guy eating Subway is at the 96 Street station platform, as seen on the wall behind the bench. The 7 train passes that station and travels on, but later when the train makes the emergency stop, it's at 96 Street.
Revealing mistake: After Fin, Martin, and the rest get what they need in the Times Square area, they get in the cab and drive off, and just as we hear on the news "Moments ago the water spout came ashore and devastated the UN," in this exterior shot we can see the taxi's back tire as it's driving down the street, but the tire's not actually moving. Presumably the taxi is on a flatbed being driven by crew while filming from this angle, hence the tire being stationary.
Continuity mistake: After April sneaks out of her hospital room, it cuts to the taxi with Fin, and the cab pulls over to the curb at the corner of Broadway and West 48, but in the closeups they're in an entirely different area - note all the buildings, then in the wide shot they're back on Broadway.
Revealing mistake: When the stewardess asks April to sign her copy of the book entitled "How to Survive a Sharknado and Other Unnatural Disasters..." it's a thin book, and in the closeup as April autographs the page we can read the text and it's actually one of the versions of the "Samsung Galaxy Tab...For Dummies" book, not April's book. Also notice when Kelly Ripa shows April's book to the audience, it's now at least 4x as thick.
Other mistake: When Lady Liberty's head rolls down the street behind Ellen, Mora, and Polly, it's a very distinctive street and there's a large white storefront sign 'Aleva' over a green awning that they all pass. Then after they drive off in the truck they're driving down that same street, even from the same direction, with that enormous head still after them. Additionally, that building with the 'Aleva' storefront and its awning has simply vanished the second time around.
