Revealing mistake: When Webster is hiding under Becker's bed and Rob/The Djinn drops Joe's body on the floor, look at his neck. You can see he still has a pulse. (01:03:45)
Revealing mistake: We are shown that Liam's camcorder has a red light on when recording. When we see the group writing out the letters, the light is off but we are shown it recording. (00:12:30)