After Julia's pants are removed, though she is left tied to the bed, in the next scene she is fully dressed.
Henry lights a lantern in the work shed. As he is struck by Michael, we can see the the lantern is extinguished before it leaves his hand.
In the scene where it is discovered the wires to the battery were cut, the electric door locks and the cigar lighter would not work.
Blood isn't bright red after it dries, after sitting on a white car door for over a day it would look brownish.