Audio problem: In the club in which Nancy is dancing (and Keung goes to talk to her), there is dance music playing. This is not a score to the film/scene, but rather an actual song being played in the club. Then why is there also a rock band playing guitars/bass/drums, and why can't we hear it? It's also quite obvious that the band isn't playing in harmony with that dance song in any form, either.
Factual error: When the hovercraft is going down the road the wrong way, a silver Hyundai Pony swerves to avoid it. It has New York plates like all the other cars on the road, but this is impossible as the Pony was only exported to Canada and could not be registered in the US as it didn't meet EPA emissions standards.