Continuity mistake: When Neville slams a mutant into the pile of boxes in the parking garage, there are brown cardboard boxes stacked neatly against the wall, but when the mutant stands up and Neville shoots him, the boxes have disappeared, showing bare wall.
Continuity mistake: When the rich middle aged couple's bodies are in front of the TV set, the man's right arm changes position from resting on the chair's arm rest in the shot over his right shoulder to elevated in the frontal shot.
Revealing mistake: After the helicopter crashes, Neville injects himself in the thigh with a syringe. A thick pad can be seen on his thigh where he stabs the needle.
Visible crew/equipment: Set lights are reflected in the glass of the helicopter before Neville takes off with the cure.
Continuity mistake: Near the beginning, Neville sees the sun just above the horizon, about to set, and he flees for his shelter, racing through city streets. As the camera repeatedly cuts to follow him, it's obvious that the sun is still high in the sky, nowhere near sunset. In fact, the sun's position is constantly changing from one shot to the next all throughout this film.
Audio problem: Neville attempts to fire at Matthias with his submachine gun, but it jams. His lips don't move when you hear him say, "Jammed!"
Revealing mistake: In a wide shot of the supposedly deserted city, car and bus traffic can be seen in the middle background at the left of the frame, driving along the roadway. (00:27:25)
Audio problem: Lisa is nude and gets up to close the windows. Neville comes out of Richie's room and turns to see the naked Lisa sitting.on the bed. You can hear her speak, but her mouth never moves.