Revealing mistake: In the chase scene in the subway, Napster stops the subway train at the end of the tunnel to block the tunnel entrance. When you see the view on his laptop, the train station CLEARLY has a metal railing. There is no such railing throughout the rest of the scene. (Yes, it's likely while filming that railing was removed to enhance the scene then put back.)
Revealing mistake: In the shots of the Metro tunnels, the "rails" are flush with the concrete surface, as streetcar tracks would be, to form a level surface that automobiles can easily drive on. In a dedicated right-of-way, however, the engineers would not go to this unnecessary trouble and expense; the rails would simply be mounted on the tunnel floor. Also notable is the presence of crossovers, but the absence of any movable switching equipment, rendering them useless.