Other mistake: In the scene where Sam, Dean and Sarah go to compare the painting to the earlier photo of it, Dean, noticing the changed position of the razor, says, "Jared, check it out." He is speaking to the character Sam. The actor's name is Jared. [Confirmed in cast interviews].
Other mistake: After the spell is cast, the ghosts are chasing Sam, Cas, the mom and the girl towards the safety line...despite ghosts being able to teleport themselves short distances, as they were doing only minutes earlier. They could easily have jumped ahead of them, instead they gave chase on foot.
Other mistake: Dean is tied to a chair when Sam rescues him. His hands are tied to the arms of the chair with rope. Sam comes over and just casually loosens the rope and it comes right off, then Dean just simply flings the rope off the other hand like they weren't even tied up, Yet before Sam got there, Dean was struggling to get loose.