Revealing mistake: When Howard shoots the subway driver near the end, we see the driver collapse and die. Where did the damage from the bullets go? There's not much in the way of bullet holes or broken glass. Certainly an automatic weapon would've produced some damage.
Continuity mistake: After Jack discovers the camera, we see what the camera is seeing in Howard's apartment on the screen. Where is Jack? He was just standing next to Annie. He should be front and center in the shot but he is nowhere to be found. The shot is wide enough that even if he was leaning out the door we'd still see him. When we see the monitor again later, he is there.
Continuity mistake: When Jack is under the bus there is a shot from the driver's side that shows the vehicle pacing the bus. The two people that were standing on that vehicle are gone. They are back the next time we see it (when the bolt snaps).
Audio problem: Annie is driving the wrong way down the street hitting cars. She starts mouthing "oh shit" but the audio suggests otherwise. She says "oh jeez."
Continuity mistake: When Sam gets shot, Annie takes the wheel back. We see the bus swerving toward the wall as Annie is grabbing the wheel. In the next shot inside the bus, she repeats the action.
Audio problem: After Sam gets shot several passengers are trying to help. One of them talks about how he's bleeding. Her mouth isn't moving.
Visible crew/equipment: After Keanu steals Tuneman's car there is an overhead shot from a helicopter as he's trying to catch up. The shadow cast by the helicopter is visible at the beginning of this shot.
Visible crew/equipment: As the bus goes down the freeway, there's a shot of the police chopper following the chase. The movie camera chopper is seen above and to the right of the police chopper that is referred to as a news chopper, but isn't seen again.
Visible crew/equipment: In the scene after the bus gets off the on ramp and hits a bunch of cars, there is a rear facing shot. The shadow of the camera that is attached to the bus is visible during most of the shot.
Audio problem: When Keanu is pulling onto the freeway in his jeep, he starts honking his horn. The actor isn't pressing the horn in the wide shot. When we see Keanu from the front he is.
Other mistake: When Jack and Harry are going down the elevator rope to the freight elevator, in the shot that shows Jack sliding down the ropes, you can see that the roof ends at floor 23 or 24, but there are supposed to be 48 floors.
Revealing mistake: When Jack is under the bus attempting to dismantle the bomb, if you look closely, when the cable comes off the hook, you get a shot of Norwood and the Lieutenant standing on the edge of the van holding the cable - you can see that it's their stunt doubles standing there.
Revealing mistake: In the elevator scene, when Jack looks up standing on top of the elevator, you can obviously tell that he is in front of a rear projection. Notice the elevator ropes don't move one bit.
Other mistake: When the safety cable goes taut and stops the falling elevator, a woman standing in the corner is shown to fall through a hole in the floor. However, the hole in the floor was plainly visible in the bottom of the elevator as it was falling. As the hole was more than wide enough for the woman's legs to fall through, she couldn't have been standing in that corner as it was falling.
Continuity mistake: When Helen tries to get off the bus, Payne blows up the door. The door is open. However, in the next shot, when looking over Jack's shoulder, the door is closed.
Continuity mistake: As Jack's initial pursuit of the bus begins, you can see although both vehicles are supposed to be traveling north on the 110 freeway, the sun changes position during filming several times. Shining on all sides for several minutes. This lasts up until the moment that Jack boards the bus.
Continuity mistake: In the shots before the bus blows up the Pacific Courier Freight plane, you can see that the vehicle towing it and the plane itself are no longer moving, as opposed to a couple of shots before this where the tow vehicle and plane are moving at a good pace. You also can no longer see the man who is supposed to be driving the tow vehicle (who might have run for it, but there's minimal time).
Continuity mistake: In a camera shot from behind the bus, it shows Traven moving the Jaguar in front of the bus. In the next camera shot from the front, it shows Traven moving the Jaguar again in front of the bus. He'd already completed the move in the previous shot.
Revealing mistake: When Traven is walking back to his car before the first bus explodes, as the bus drives past him, you can see from the shadow it casts that the bus isn't driving straight on. It turns the corner behind his car. Obviously a prop bus is further down the street and that is the one that blows up in its place.
Continuity mistake: The bus hits a car and wrecks the driver's side indicator. Later on however, the indicator is fixed.
