Continuity mistake: At the end of the film when Lucifer has ripped open Constantine's shirt and removed tar, immediately after when he goes back to Angela, the shirt is suddenly done up again. (01:44:35)
Continuity mistake: At the end (after the credits), when Constantine place the lighter on Chas' grave, Constantine's fingers on the lighter change position in the close-up view. (01:54:50)
Continuity mistake: There is a close up shot, when John slits his wrist, of the blood seeping around his watch. It is an integral part of the scene, yet moments later, when viewed from above, the blood is nowhere near the watch.
Factual error: Rachel Weisz fires approximately 29 shots from her semi-automatic handgun without reloading - vastly more shots than her gun can hold.
Factual error: When Angela talks to a priest about giving Isabel a Catholic funeral, the priest says that it's impossible because Isabel committed suicide. Even though the church does consider suicide a mortal sin, this rule doesn't apply to people who have a history of mental illness.
Factual error: After John traveled to hell using Duck the cat, he and Angela are going to eat something and John tells about his suicide attempt. In this flashback, you see them using a defibrillator to shock him back to life. When he is shocked, people are touching his body, but they don't get shocked.
Other mistake: In the scene where John is in the apartment with the cat and Angela closes the door, John then says her name to get her to reopen the door. He says the wrong name, "Rachel" (the actress' name) instead of "Angela" (the character's name).
Other mistake: When John puts the needle on the first track of Dave Brubeck's "Time Out" album, "Take Five" begins to play. "Take Five" is the third track.
