Revealing mistake: When Imhotep transports Evie, Beni and himself back to Hamunaptra, Evie hears the plane and looks up. Before she states "O'Connell," you can see the letters and numbers on the side of the plane are backwards, like a mirror image - it says "B5538" backwards, which resembles "BE228" (no mirror). (01:32:15)
Revealing mistake: In almost every scene that the crab is in, just watch the space above it and you can see strings moving it.
Revealing mistake: During the fight scene on the riverbank when the white haired man lands on the pavement, the "concrete" pavement moves.