Visible crew/equipment: When Mia and Brian are about to jump off the roof, when a gunman takes aim there's a cameraman to the bottom right below him. (00:32:35)
Continuity mistake: When Mick and Maggie are talking in the kitchen after spending the night together, Mick pours himself a glass of orange juice and sets the carton down on the counter. The carton is initially in front of the glass, but then moves to sitting next to it. (00:43:55)
Revealing mistake: When Wil is showing Sylvia how to shoot, and she fires, Justin Timberlake can be seen wearing earplugs. When the scene cuts, he no longer is wearing them.
Factual error: When Watson is looking at the spiderweb of clues in Holmes' apartment, he is shown a newspaper article about the bombing and doctor's death. The lower left of the clipping shows a story with title "Soviet Government Money For The General Strike." The movie is set in 1891, and the term Soviet first came into use in 1905 to describe a worker's movement in Russia, but a Soviet Government didn't exist until 1917. (00:16:00)
Continuity mistake: When Reid and Kato are fighting by the pool, the beach ball falls off the chair (beside the pool) when they land in the water, but is back up on the chair in a following shot. (01:12:25)