Factual error: General Ross and Blonsky are shown in their Class A uniforms, and both of them are missing their U.S. insignia on the collars. Also, General Ross is shown wearing the infantry cross rifles branch insignia on his collar, but he would not wear a branch insignia as a general officer. I could give Blonsky a pass since he's a British officer wearing an American dress uniform for reasons not explained onscreen, but Ross should have known much better as a general with decades of service. (00:30:10)
Other mistake: When Bruce is riding his bicycle to deliver pizza to the University, you hear him ringing a bicycle bell while he says, "Excuse me". If you look at the bike he's riding, there's no bell to be found. (00:36:00)
Revealing mistake: When the Hulk walks through the stream, the water doesn't react to his feet. (00:59:20)
Audio problem: When the general asks how Blonsky was doing, he doesn't open his mouth. (01:07:40)
Continuity mistake: When Dr. Ross and Bruce are in the hotel room, Banner empties the purse on the bed and there is some cash inside the wallet. As they are about to leave he picks up the cash, which isn't in the wallet anymore. (01:08:10)
Factual error: When Bruce and Betty are attempting to drive into New York, they get stopped at a police roadblock at the tunnel entrance and start walking instead. When we see them crossing a bridge, a sign says "No Wake - Speed Limit 9km\H. Being in the United States, this would be miles per hour or knots, not kilometers. (01:11:50)
Continuity mistake: During the street chase in Brazil, the time of day changes from night, to perhaps late afternoon/evening, to night again.
Continuity mistake: At the beginning of the movie, when the general wears his dress greens, his epaulet rank has the stripe near his neck. Later,in a shot about halfway through, the stripe is near his shoulder.
Continuity mistake: As Emil is in the men's restroom looking at the mirror, some of his hair is hanging over his forehead, but when the shot changes, his hair is suddenly brushed back.
Continuity mistake: When Bruce and Betty are hugging on the bridge, they turn back and forth about a quarter of a turn whenever the camera angle changes.
Factual error: When the police are searching for abomination in New York City, they reach an alleyway where there's a police car marked 'Toronto Police'.
Continuity mistake: When Hulk throws the chunk of sheet metal at the helicopter, it glances off the rotor housing (taking a ragged piece with it.) When the chopper crashes, however, the propeller comes off with a perfectly clean edge, as if the projectile had sheared completely through the base.
Factual error: The USB drive should have been destroyed after sitting in Bruce's stomach for a day, or at least been somewhere in his intestines, so he wouldn't have been able to puke it up.
Continuity mistake: After the first time we see Bruce transform into the Hulk, he has hitched a ride with the elderly man. You will remember he has 3 1/4 length pants on with a few rips. It cuts to a quick clip of him walking up the road but this time he has full length pants on. They switch back to shorter length pants straight after.
Other mistake: Bruce is seen wearing a Polar F5 heart rate monitor in a couple of scenes after Betty gives it to him (such as when he is in bed with Betty) but there is no transmitter strap around his chest, which that model needs in order to pick up the wearer's heart rate.