Revealing mistake: During the opening, where we see a new Tall Man emerge from the portal and toss his decomposed body from the second movie into it, the actor's reflection is visible in the metal portal poles as he waits for his cue to 'materialize' in the room.
Revealing mistake: When Reggie and Tim the sheriff's son are in the funeral home and get confronted by the two black women, the silver ball comes to attack and kills one of the women. Tim saves the day with a revolver, but when he spins the cylinder before firing, you can see all of the cartridges in the gun have already been fired: dimples in the centre of each casing.