Continuity mistake: Near the middle of the film when Joey gets arrested and is being walked down the stairs outside. If you look in the front halfway down the stairs you can see a guy holding a brown box, but when the camera cuts to a face shot of the black man in front of the camera the man holding the box has disappeared, but he should still be visible because he was only half way down the stairs.
Plot hole: When they are on the subway train, they are talking about the worm and the virus. They said that everything would happen on the 14th. A couple of scenes later, when they are setting up for the traffic lights to go crazy at 9:00, Dade looks at his watch. You can see the date as 10-18, which is 4 days afterwards.
Trivia: When MGM/UA set up a website for Hackers, it was like dangling candy in front of a child. Soon after the site was established, it was hacked! A group calling itself the Internet Liberation Front managed to 'doodle' all over the photograph of Hackers stars Angelina Jolie and Jonny Lee Miller, and replaced verbiage, 'this is going to be an entertaining, fun promotional site for a movie,' with 'this is going to be a lame, cheesy promotional site for a movie!' The studio decided to maintain the site during the theatrical run of the movie in its altered form."