Continuity mistake: After the explosion in the laboratory, Josh is laying on the floor, injured. His face is covered in blood, however during the scene the amount of blood on his face keeps changing. In close ups of his face his lips are free of blood, but in wider shots his lips are covered in thick amounts of blood.
Continuity mistake: Towards the end of the Beaumont party scene, Alex and the security guys are in the hallway with the killer statues. One of the security men falls to the floor and his earpiece falls off. Throughout the scene, it keeps changing position from being on the floor next to him, to back on his ear, to being on his ear in a different position.
Plot hole: The Djinn grants two wishes to Alex's boss: One for making the item on his desk "100 times more valuable", then granting him $1 million by having his mother die in a plane crash. He is only able to grant one wish to a person (save for the one who releases him from the Opal). The Djinn directly states that he can't grant more than one wish to a single person in the second film, when the Russian asks him for a second wish.
Revealing mistake: After the Djinn escapes and there's an explosion in the lab, you can see some stuff on the ground that looks like it's on fire. The objects are not actually burning, the fire is being produced by a burner. There's no smoke from the objects, which is a dead giveaway that they're not actually "on fire."