On the ship, the female fighter is wearing boots; when shown resisting arrest, she is wearing sandals.
When "Doctor Spider" is using the C.B. radio on his car to announce to K1 Steinberg and Mason have been killed, the answers from K1 aren't heard (they can be guessed by Spider's lines) but they should. It's not a phone, it's a radio with a loudspeaker.
The blue car doesn't have a front plate.
At take off we see an Eastern Airlines Boeing 727, a narrow body aircraft (with one aisle). However, the shots inside the aircraft show a wide body aircraft (with two aisles), and this cannot be inside a 727!
When Hill is riding the water scooter he is wearing his red cap, however in the shots from above the cap is blue.
(at around 1 min) The helicopter seen is a Bell 206 Jet Ranger, which is equipped with a turbo-shaft engine (a form of jet engine / gas turbine, optimized to produce shaft power, rather than jet thrust). But when the engine starts, the sound of a piston engine can be heard instead.
Roscoe's vocal chords do not move when he's heard using his ventriloquist voice to fool the cops.
A mic and a head of crew member are visible as a reflection on the back seat's right window as "La fatalona" drives the car after "Rosco" blows the CIA car.
There are no explanations how one can go from the Italian restaurant's restroom to a boat in the middle of the sea, and back.
The two heroes are mistaken for secret spies, because the spies were late. But the real spies never come to unmask them.
CIA head tests the bulletproof car by shooting at it. It's very dangerous because of the ricochets.