Continuity: When the Djinn is held at gun point in the museum, the guy that is supposed to be frozen can be seen moving.
Revealing mistakes: When the broken, glowing, red jewel is moving on the floor, someone is clearly shaking the section of flooring to make the jewel move. From the right side, the flooring can be seen moving up-and-down quickly to make it move.
Plot holes: The first victim of the Djinn wished he'd never been born and his wish was granted. That should mean that his girlfriend and everyone else who knew him should have their memory of him wiped clean. She should not be grieving for him.